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© Raymond Pettibon 


RESEARCH LIBRARY 
Pe GEL RESEARCH INSTITUTE 


JOHN MOORE ANDREAS COLOR CHEMISTRY LIBRARY FOUNDATION 





A 


LABORATORY MANUAL 


CONTAINING 


DIRECTIONS FOR A COURSE OF EXPERIMENTS IN 
GENERAL CHEMISTRY 


Spstematically Arranged 


TO ACCOMPANY 


THE AUTHOR’S ‘ELEMENTS OF CHEMISTRY ” 


‘ 


BY 


IRA REMSEN 
President of the Johns Hopkins University 


THIRD EDITION, REVISED AND ENLARGED 





NEW YORK 


HENRY HOLT AND COMPANY 
1905 





Oe Copyright, 1889, 1890, 1902, 
‘ene : eri bye hr ee 


HENRY HOLT & CO. 











a 


‘a 









+ 


’ 


to 
Pay see, 
De Fly 


i 


NOTE FOR TEACHERS. 


ON comparing the experiments described in this Manual 
with those described in my ‘‘ Elements of Chemistry” it will 
be found that some of the more difficult ones have been 
omitted here. As many as possible of those omitted should 
be performed by the teacher in the presence of the class ; 
and the points of importance should be drawn out by ques- 
tions put to the members of the class. A number of ex- 
periments not included in the text-book are also described. 
To avoid confusion, the experiments are numbered to cor- 
respond with those in the ‘‘ Elements,”’ the additional ones 
being designated as a, 5, etc., as for instance 106a. After- 
wards the pupils should write a full account of what they 
have seen, and draw such conclusions as the experiments 
may lead to. 

THE AUTHOR. 


PREFACE TO THE SECOND EDITION. 


In this revised edition of the Manual particular attention 
has been given to the statements of quantities to be used, 
with the object of helping the teacher and the pupil as 
much as possible. The new edition differs from the old 
also in this respect, that it contains a brief, though sys- 
tematic, course of experiments in qualitative analysis. The 
author has endeavored to treat this part of the subject. 
rationally, so as to make the work valuable as a mental 
discipline, and to discourage the purely mechanical work 
which is too often done under the name of qualitative 
analysis. 

Ln: 
(iti 


PREFACE TO THE THIRD EDITION. 


THis Manual has again been subjected to a thorough re- 
vision. In the main it has not been materially changed, 
but such additions and corrections have been made in it as 
were necessary to bring it into conformity with the new 
edition of the ‘‘ Elements of Chemistry,” which has just 
been prepared. 

I take this opportunity to thank Dr. C. E. Waters for 
his valuable aid in the work. 


I. R. 


iv 


APPARATUS AND CHEMICALS. 


For the benefit of those who have no laboratory at com- 
mand, and who may wish to make arrangements for per- 
forming the experiments described in this book, the 
following lists have been drawn up. In them is included 
everything necessary to perform the experiments on a small 
scale. Should it be desired to fit up a room with conven- 
1ences for students, the amount of apparatus necessary will 
depend upon the number of students, but for each in- 
dividual the expense will be small, as some of the pieces of 
apparatus, such as the magnet, weights, scales, etc., need 
not be multiplied. In place of some of the pieces of ap- 
paratus described in the book, ordinary kitchen utensils 
willanswer. Thus, for example, instead of the trough for 
collecting gases, a tin pan or a deep earthenware dish may 
be used; instead of the water-bath, a stew-pan, fitted with 
two or three different-sized tin or sheet-iron rings; in place 
of glass cylinders for working with gases, wide-mouthed 
cheap bottles; and in place of Woulff’s bottles, wide- 
mouthed bottles fitted with a cork having two holes. In 
case of need nearly everything necessary can be procured 
at an ordinary drug store, though nowadays there is no 
difficulty in getting the simpler forms of chemical appara- 
tus at little cost. 

The publishers do not deal in chemicals and apparatus, 
nor, they may as well say, recelve commissions on them. 
Any orders should be sent direct to the dealers. 

Messrs. Kimer & Amend, Nos. 205 to 211 Third Avenue, 
New York, whom the publishers take the responsibility of 
recommending as thoroughly reliable, will furnish each of 
the following articles at the price given. 

If several pieces of the apparatus in List No. 1 are taken, 
a discount of 10 per cent will be made; on a complete set 

Vv 


20 per cent discount will be allowed; on three or more sets, 
25 per cent. 

A discount of 10 per cent will be given on a complete 
set of the chemicals, and of 15 per cent on three or more sets 

For a class of 12 three or four times the amount of ap- 
paratus included in List No. 1 could be made to answer, 
particularly if the pupils are not all required to do the 
same thing at the same time. As there is, however, always 
more or less breakage of glass- and porcelain-ware, it is 
well to have extra pieces of ali such apparatus on hand. 

As regards chemicals, List No. 2 gives quantities re- 
quired for a class of 12 as nearly as can be estimated. It 
is better to have somewhat larger quantities, as some of the 
experiments may have to be repeated a number of times. 

For most items less than the whole set, there will have 
to be a small additional charge for packing. It should be 
borne in mind, however, that usually the charge for pack- 
ing one article must be as large as for.several. Some articles 
can, of course, be mailed without any charge for packing. 


Lisr Nov 1: 


A list of apparatus and chemicals necessary for perform- 
ing all the experiments described in this book. 
eran Tubes, one 10 in., one 


APPARATUS. 1 Ges Boitle, 8 oz., with 2-hole R 
Stopper 30 
1 Nest Beakers, 1-3........ meee $0 35 | 14 1b. Assorted Glass Tubing, 4-7. 25 
1 Jeweller’s Blowpipe, 8in...... 10 | 44 lb. Assorted Glass Rods........ 15 
7 Wide-mouth Flint Bottles, two 2 Sheets each Red and Blue Lit- 
each, 2, 4,8 0z., and one 820z. 40 mus-paper...... Roe oe A eae 12 I 
i Bunsen Burner with regula- 1 Horseshoe Magnet, Binsswees.e 12 
tor, or 6 oz. glass aleohol 1 Porcelain Mortar and Pestle, 
lamp, saine price..........-. 40 S16 IN, . os es eens be lean eee 45 
Dizi URAbUDe a re eee eae 25 1 Piece Platinum Foil, 1x 14in.. 1 00 
2 doz. Assorted Corks........... 20 6 in. Medium Platinum Wire.. —~«6BO 
1 Set Cork: Borers, 1-677 202 6 1 00°} 1 Plain Retort} $8 070772) 22 
1 Nest Hessian Crucibles, 1 Stoppered Retort, ISloziee eee 45 
= EHPOGS © bos: apistceie sanete pee 5 3 ft. Rubber Tubing for gas,14in. 39 
2 114 in. Porcelain Crucibles..... 36 (Only needed if Bunsen 
1 25.¢.c, Grad Cylinder. soa. 35 Burner is used.) 
1 Deflagrating Spoon............ 15 2 as Panto cues (FoR, ¢ connec- 
1 Dropping-funnel, 50 ¢. ¢:....... 1 00 ns).. a tra ee! 2!) 
1 each Evaporating Dish, 6 and 1 316 in, Sand Bath............. ae £9 
Oba LM Stevia che telaheters tater ole ate n 35 1 Hand Scale, ce welgne ny elete a85 
1 Lead Dish, 2in....... See et 12 1 Test Tube Stand State Sita) ee 
1 Round Wile, 5 an. cnaveesee ne oer 20 | 12 Test Tubes, 5 inert ee APs Sc 
1 Triangiwlar Wile: ON sas se seer 20 1 Test Tube Brush..... aivisin et a) me 5 
1 Pack White Filters, 4in........ 13 1 Test. Tube Clatipie....:0oe7 eens eee 
4 Flasks: one 4 oz., two 8 0z., I Tron Eripod: Ss. cs0e eee 30 
ONGC OF.j2, juidn sk came sie OD 1 Filter-stand (rings) sesso 45 
1 Steel Forceps....... ba, ue ewe 20 1 Wire Triancles.2nce. ae pees 5 
2 Hunnelsi2h6 aa ee ene ee 22-in Watch-glasses. ..ie...sceca 10 


vi 


1 Piece Wire Gauze, 6/°x6/’. ....$0 » 2 oz. Lead Carbonate..........-.$0 10 
1 Piece Blue Glass, 2/” x 2’’....... LOZ Me A COLALEs coeur pie eee 10 
1 PieceGround Glass, thin,4’’ x 4’/ se 2 OZ, Gad (ANIL ELLE ie oss apace sola 10 
1 5-in. Water-bath.. 90 NOZjc 8 Peroxide... 10 
2 Wire Clamp Supports.. SacI ees « 1 60 4oz. ‘* Sheet.... 10 
—— 20z. ‘* Sesquioxide.. 10 
$16 64 oo art pad SeRkt sc ee UU, 
ram Magnesium Ribbon..... 10 
CHEMICALS. 1 oz. Magnesium Sulphate.. 10 
40z. Acid Acetic, pure (bottle 5 1lb. Manganese Dioxide, pow. 
cents extra).............. Bee POO CELed Bite caae ae aoe ea eee 10 
4 oz. Acid Arsenious.. .......... 10 2 OZ. Mercuric Chloride. . . 15 
16 oz. ‘** Hydrochloric (bottle CiOZ MOLCUL Ya ren sess on 15 
15 cents extra)..... ......... 1 oz a ed Oxide. . eee O 
8 oz. Acid Nitric (bottle ; 12 cents 1 oz. Nutgalls, powdered... Soaccee 10 
extra) . 10 2 oz. Paraffin.. 10 
2 0z. Acid Oxalic.. 10 1 oz. Phosphorus (bot. 10c. extra) 15 
16 OZ, .0)5* Sulphuric “(bottle ‘2 1 dram Potassium.. SF 380 
GCMENTOXELA) ee sein siidits has ee 10 2 OZ. on Bromide.... .. 10 
MO. ACIATPATEATIC. .. jc sis a oa = 10 4 oz. wd Carbonate 
20z. Alcohol, for experiments (bottle 5 cents extra).. 10 
only (bottle 4 cents pag 5 oY) 4 oz. Potassium Chlorate. 10 
8 oz. Alum..... Riss ce ae eee 10 1 oz. | - Chloride........ 10 
4 oz. Ammon. Chloride. . 10 1 oz. he Chromate....... 10 
8 oz Y Hydrate, concen- 4 oz. 3 Bichromate..... 10 
trated (bottle 10 cents exirs), 10 2 OZ. a Ferrocyanide.. 10 
4oz. Ammon. Nitrate ...... .... 10 1 oz. a Ferricyanide.. 10 
1 oz. Ammonium Oxalate...... LO 4 oz. Ue Hydrate Sticks 
20z. Antimony, powdered....... 10 (bottle 5 cents extra).. 20 
2 Oz. Me and Potassium 1 oz. Potassium Iodide (bottle § 5 
Tartrate.. . Wis ghee alias. OO cents extra) . sh 25 
2 oz. Barium Chloride. Apes he Armee 10 4 oz. Potassium Nitrate......... See 
4 oz. Calcium Chloride, fused.. 10 2 OZ. ‘“ , Permanganate.. 10 
1 02. 2 Carbide (bottle es 1 dram Sodium (bot. 3c. extra). 10 
cents extra)..... 10 20z. Sodium Acetate, fused...... 106 
4 oz. % Sulphate ......... 10 2 oz. ve Bicarbonate.. Ree aK 
PLOZAODICMOALS fais cies pres se ¥ 10 4 oz. - Biborate (Borax)... 10 
4 oz. Carbon Bisulphide (bottle 5 4 oz. ee Hydrate (bottle 5 
RCOMESIORTRA) Ade os oct e\cisinw snes 10 cents extra)........ ek oe Rees nee 20 
8 oz. Animal Charcoal, powdered 10 4 oz. Sodium Nitrate. .... eanteke eratate 10 
SOW OPCs BOW seis oe os 20 2 OZ. % Phosphate..... .. 10 
4 oz. a Sulphate......... aot) 240 4 oz. Se Sulphate........... 10 
1 oz. ie (O52 Gre a eee is 1 0z. Sol. of Platinum Chloride... 7 
4 oz. Fluor Spar, powdered...... 10 SoZ Sul pul, TOM a osc ves ccs ce 10 
leisy as al IEG fetes Re a a LO AtOZ DIN PO rANUIALEG so. snacieeen bee LO 
1 oz. Iodine (bottle 2cents extra) 30 | 16 0z. Zinc, granulated........... 20 
4 oz. Iron Filings, fine.... ..... 10 OZ ee UDR ALC ons. sense oe LC 
8o0z. ‘* Sulphide........ a 10 —— 
SO UD RALG, se, cacevee ss 10 $10 21 
List No. 2. 
40z. Acetic Acid (pure) bottle 40z. Alcohol (bottle 5 cents 
HiGeNtS OXtra) so. ..ce cseess $0 10 OXtla). ase eee Pa asieite ies $0 15 
4 oz. Acid Arsenious............. 10 PAE TAIT. cals vas iirc. ic ae Bn aes 15 
6 lbs. Acid Hydrochloric (bottle 1 1b. Ammonium Chloride....... 12 
2o.cents extra) ....... ..... 30 1lb. Ammon. Hydrate (Conc.) 
4 lbs. Acid Nitric (bottle 20 cents (bottle 15 cents extra)........ 20 
extra) . 2) ORO SPAOnOe. sate) 1lb. Ammon. Nitrate poe 10 
8 0z. Acid Oxalic..... 10 cents extra) .... Ateg sn. Pas 
91bs, Acid Sulphuric ‘(bottle 25 4 oz. Antimony (powd.) . 15 
GONESIOSEFA)., 0 os5c se sacces 45 2 OZ. of: and Potassium 
20z. Acid Tartaric........... raat? 10 Tartrate ........ Fancricianuonrc - 20 


2 lbs. Animal Charcoal...... $0 20 4 oz. Phosphorus............-. ++ 


4 oz. Ammonium Oxalate. . 25 2 oz. Platinum Bere (solu- 
2 oz. Barium Chloride... ... 10 tidn). . Aes sku ae osiea eaten etl OO 
8 oz. Calcium Chloride...... 12 2drams Potassium ...... ...... 
8 oz. nt Carbide....... 1 lb. ~ Bichromate.. 
1 Ib. ES Sulphate ..... . 10 4 oz. a Bromide..... 
8 oz. Cale Spar.... ... Stage 1G 1 Ib. ‘“* Carbonate ge 
1 lb. Car bon Bisulphide (bo ‘e tle 10 cents extra) . ....... 
10 cents extra)........... 7 RO 21bs. Potassium Chlorate........ 
2 Ibs. Copper Foil . Een SEG a 2 OZ. 5 Chloride........ 
2 OZ. Oxide choc ah 20 4 02. os Chromate... .. 

46 lb. “ Sulphate.. ie eRe ES 4 0z. se Ferricyanide.... 
“8 oz. Fluor Spar Wpewd- ).. Rie has ECoetel 4 OZ. o Ferrocyanide. . 

16 1b. Granulated Tin. Fi atest, ee tolea eer : Hydrate (bottle 
1 OZ MMOIL Oa ouieh er naNe et nee 10 8 cénts extra)... 0... seeceec 
1 oz. Iodine (bottle 2 cents ex) Ay 380 2 oz. Potassium lodide........... 
8 oz. Iron Filings............. a 10 | % be A Nitratecs.c sce. 
BOF. enh UD OGOad as se Keer + 10 40 nt Per: ita Sent 
2lbs. “ Sulphide.......-... Re ele 1 1. Roll Sulphur.. 

14 lb. Lead Acetate...... Retin 10 1 oz. Sodium (bottle "4 cents 
4 OF ECArbONnaLe.r: bon "sc wees 10 extra) .. 

LOZ CE UNIDPALG ta das elem oheieicre 10 8 oz. Sodium Acetate ‘(bottle | 8 
20z. ‘* Peroxide..... ines ie To cents extra)........ mers 
40z. ‘* Sesquioxide........ .. 10 44 lb. Sodium Bicarbonate....... 
Tlbs gen a, Sheet aes Genesee 40 4 oz. eS Biborate (37.2020. 
2 O%s LAPIS  aacersgon ciaccleck ec eine 10 2 OSsamees Hydrate Ha Stes 
2 lbs. Manganese Dioxide(coarse- 1 Ib, A INICTAtG: caw ser 

ly granulated).... ........:« 30 4 oz. rh Sulphate. ood eee eents 
4 oz. Mercuric Chloride... ...... 385 3 lbs. 3 ZUG oe eters sees 
BiOZe MeFCUTrY fae eeaeminee seer ae 50 4 OZ. ‘Zinc Sulphate .......-..06.. 
4 oz. Merenen Red:Oxide...2... 30 — 
1 oz. Nutgalls, powdered... ... 10 $18 11 

viii 


LIST OF EXPERIMENTS. 


. Decomposition of sugar by heat. 
. Change of mercuric oxide by heat. 
. Action of hydrochloric acid on cale-spar or marble. 


Action of nitric acid on copper. 


. Action of sulphuric acid on zine. 


Burning magnesium ribbon. 


. Action of nitric acid on tin. 

. Action of tartaric acid on bicarbonate of soda, dry and wet. 

. Action of iron sulphate on potassium ferricyanide, dry and wet, 
. Mechanical mixture (iron-filings and sulphur). 

. Mechanical mixture examined. 

. Effect of heating a mechanical mixture of iron and sulphur. 

. Heating lead in the air. 

. Heating zinc in the air. 

. Heating tin in the air. 

. Heating lead, zinc, and tin protected from the air. . 


18. Burning a candle in a closed space. 


18a. Filling vessels with a gas by displacing water. 
186. Oxygen from mercuric oxide. 


20. 
21. 
22. 
_ 23. 
2A. 
25. 
26. 
27. 
28. 
29, 


30. 
31. 
32. 


* 33. 
35. 


Oxygen from potassium chlorate. 

Oxygen from potassium chlorate and manganese dioxide. 

Action of oxygen at ordinary temperature. 

Burning sulphur in oxygen. 

Burning charcoal in oxygen. 

Burning phosphorus in oxygen. 

Burning a steel watch-spring or picture-wire in oxygen. 

Nitrogen: preparation and properties. 

Water from wood and from meat. 

Crystallization of alum, and presence of water of crystalliza- 
tion in the crystals. 

Water of crystallization in gypsum. 

Water of crystallization in copper sulphate. 

Efflorescence as illustrated by sodium sulphate and sodium 
carbonate. 

Deliquescence as illustrated by calcium chloride. 

Decomposition of water by sodium. 


ix 


. Preparation and properties of hydrogen. 
. Purification of hydrogen. 


| rightness of hydrogen. 


. Burning hydrogen from platinum tip. 

. Hydrogen burns, but does not support combustion. 
. Ammonia from ammonium chloride. 

. Preparation of ammonia. 

. Preparation of nitric acid. 

. Properties of nitric acid. 

. Action of nitric acid on copper. 

. Preparation of nitrous oxide. 

. Properties of nitrous oxide. 

. Preparation of nitric oxide. 


Properties of nitric oxide. 


. Preparation and properties of chlorine. 

. Burning hydrogen in chlorine. 

. Hydrochloric acid. 

. Hydrochloric acid: preparation and properties. 


Formation of salts. 


. Bone-black filter. 

. Reduction of copper oxide by charcoal. 

. Reduction of white arsenic by charcoal. 

. Preparation of marsh gas. 

. Preparation of acetylene. 

. Carbon dioxide from the lungs. 

. Carbon dioxide from carbonates. 

. Preparation and properties of carbon dioxide. 
. Formation of carbonates. 


t Action of carbon dioxide on lime-water. 


. Carbon monoxide. 

. Reduction of copper oxide by carbon monoxide. 

. Flames. 

. Bromine from potassium bromide. 

. Action of concentrated sulphuric acid on potassium bromide. 
. Iodine from potassium iodide. 


Iodine: properties. 


. Action of concentrated eal pane acid on potassium iodide. 
. Etching by hydrofluoric acid. 
. Distillation of sulphur. 


Crystallization of sulphur. 


. Action of sulphur on copper. 
. Preparation and properties of hydrogen sulphide. 
. Action of hydrogen sulphide on the solutions of some com- 


pounds. 
x 


96. Preparation and properties of sulphur dioxide. 

97. Bleaching by burning sulphur. 

97a and b. Properties of sulphuric acid. 

98. Action of phosphorus and iodine. 

98a. Phosphoric acid. 

99. Arsine. 

100. Detection of arsenic _ Marsh’s method. 

101. Detection of arsenic by reduction of oxide. 

102. \ Stibine 

103, f Stibine 

104. Potassium carbonate from wood-ashes. 

105. Decomposition of water by potassium. 

106. Potassium iodide, examination of. 

106a. Preparation of potassium hydroxide. 

107. Gunpowder. 

108. Action of ammonia on acids. 

109. Heating ammonium chloride. 

110. Flame-reactions. 

110a. Detection of potassium, sodium, and ammonium. 

111. Preparation of calcium chloride. 

112. Lime-water. 

113. Plaster of Paris. 

113a. Gypsum. 

115. Copper sulphate. 

116. Copper oxide and hydroxide. 

1l6a. Detection of copper. 

117. Silver nitrate, preparation. 

118. Silver chloride, bromide, and iodide. 

119. Iron; ferrous chloride; ferric chloride. 

120. 

121. 

122. Action of potassium chromate and potassium bichromate on 
hydrochlorie acid. 

123. Chromates. 

123a. Comparison of sulphates and chromates. 

123b. Detection of chromium. 

124. Lead-tree. 

' ]24a. Action of water on lead; on iron. 

125. Red lead. 

126. Lead peroxide. 

127. Fermentation. 

128. Soap. 

129. “Temporary hardness.” 

130. “ Permanent hardness.” 

131. Tannie acid. 

132. Chlorides. 

133. Nitrates. 

134. Sulphates. 

135. Carbonates. 

136. Sulphides. 

How to analyze substances. 


Potassium chromate and bichromate. 
















137. Study of Group I. 

138. Study of Group IT. jo) Wal aan 

139. Aluminium. ) Bree Yas 

140. Chromium. Poe Gees 

14]. Iron. a Heaths 

142. Zine. Bae nate os 

143. Manganese. £3 

144. Separation of elements of Group TOT. «cient Gh aig ene ie 
145. Calcium. UE Se 
146. Barium. Se [rea 

147. Magnesium. Reece occ) 

148. Study of Group VI. iw arg 

General Directions. ‘SOR ae 


Weights and Measures. 


LABORATORY MANUAL. 





GENERAL LABORATORY DIRECTIONS. 


1. Neatness is one of the first conditions of success 
in chemical work. Keep your laboratory desk, as well. 
as all your apparatus, clean. 

2. Provide yourself with a working-apron to protect 
your clothing. | 

3. Always have a decent towel available. 

4, In observing use your own eyes. 

5. In describing experiments use your own words. 

6. In thinking over the results use your own mind. 

7. An experiment should be repeated as many times 
as may be necessary to secure accurate work. 

8. If the results obtained are not those which you 
have been led to expect, try in every way you can 
think of to find out what the matter is. See first 
whether you have worked exactly as directed. 

9. After an experiment is finished, write in your 
note-book in the laboratory an account of what you 
have done. If you are able to draw any conclusions 
from what you have seen, state what these conclusions 
are. Write the description accurately and in as good 
English as possible. Do not use abbreviations. In 
referring to chemical substances do not use simply the 
symbol, but the full name with the symbol after it. 
Thus, potassium chlorate, KC1O,; hydrochloric acid, 


HCl. Further, in speaking of chemical substances 
do not use symbols. For example, do not say, “1 
poured some H,SO, into an H,O solution of BaCl,,’ 
but say in English what you did. 

10. After you have written an account of an experi- 
ment have it examined by the teacher before you go 
on to the next one. 

11. Always read before and after an experiment or 
a set of experiments that part of the text-book in 
which the experiment or experiments are referred to, 
and keep reviewing constantly. 

12. If an experiment not included in your course is 
performed by you or by your teacher, write an accrrate 
account of it as if you had yourself performed it, but 
do not make any statement without entirely satis- 
factory reasons for making it. 

13. In working with gases see that all the joints of 
your apparatus are tight. 

14. In case of fire a moist towel thrown over the 
flame will generally be sufficient to extinguish it. 

15. Acid wounds should first be washed out, and a 
paste of sodium bicarbonate and water then applied. 

16. Burns should be treated with a paste of sodirm 
bicarbonate and water. 





HEAT AND CHEMICAL CHANGE, 


EXPERIMENT 1. 
Test-tube: sugar. 


In a clean dry test-tube put enough white sugar to 
iy make a layer 4 4 to $ inch thick. Hold 
fy the tube in the flame of a spirit- lamp 
or laboratory burner as shown in 
Fig. 1. Heat until no more fumes are 
given off. 

What changes take place ? 

What do you see on the sides of the 
tube ? 

What is the color and taste of that 
«which remains behind ? 
ee Does it dissolve in water ? 

Is it sugar ? 

Is the change which has taken place chemical or 
physical ? 

What caused the change ? 








HEAT AND CHEMICAL CHANGE. 


EXPERIMENT 2. 


Glass tubing % inch internal diameter; file; mercuric oxide; 
splinter of wood. 

1. From a piece of glass tubing of about $ inch inter- 
nal diameter cut off a piece about 4 inches long by mak- 
ing a mark across it with a triangular file, and then seiz- 
ing it with both hands, one on each side of the mark, 
pulling and at the same time pressing slightly as if 
to break it. Clean and dry it, and hold one end in the 
flame of a laboratory burner until it melts together.* 
During the melting twirl the tube constantly between 
the finger and thumb so that the heat may act uni- 
formly upon it. After it has cooled down put into it 
enough red oxide of mercury (mercuric oxide) to form 
a layer + to } inch thick, 

2. Heat the tube as in Experiment 1. 

What change in color do you notice? 

What is deposited on the sides of the tube ? 

3. During the heating insert into the tube a splinter 
of wood with a spark on the end. 

What follows? 

‘4. Take it out and put it back a few times. 

Is there any difference between the buenas in the 
tube and out of it ? 

What difference? 

How do you know that the red substance which me 
put into the tube has been changed ? 

Is the change chemical or physical ? 

What caused the change ? 


* Such a tube is called an zgnition-tube. 





CONTACT AND CHEMICAL CHANGE. 


EXPERIMENT 3. 


Small piece of cale-spar or marble ; ignition-tube ; dilute hydro- 
chlorie acid; small porcelain evaporating-dish; water-bath; test- 
tube. 


1. Examine a piece of cale-spar or marble. Notice 
whether it is hard or soft. Heat a small piece in a 
glass tube such as used in Experiment 2. 

Does it change in any way? 

Does it dissolve in water? In order to determine 
whether a substance is soluble in water or’ not, boil a 
small piece with distilled water.* Pour off a few 
drops of the water on a piece of platinum-foil+ or a 
Me an heat gently to evaporate the water. 

If there is anything solid in 
solution there will be a solid 
residue left on the foil or 
watch-glass. If not, there 
will be nothing left. 

2. Knowing now the gen- 
eral properties of the calc- 
spar or marble you will be 
able to determine whether 
it ig changed or not. Treat 
¥ a small piece with dilute hy- 

Fia. 2. drochloric acid. 

What takes place ? 

3. After the action has continued for about half a 

* Rain water may be used instead of distilled water. It is better than 
ordinary drinking water. 

¢'The expensive metal platinum is much used in chemical labo- 


ratories, for the reason that it is not easily changed chemically by heat 
or by most substances used in the laboratory. 








EXPERIMENT 3—(Continued). 


minute insert a lighted match in the upper part of the 
tube. | 

Does the match continue to burn ? 

Does the substance in the tube burn ? 

Is the invisible substance in the upper part of the 
tube ordinary air? 

How do you know ? 

Does the solid substance disappear ? 

4, In order to tell whether it has been changed 
chemically, the hydrochloric acid must be got rid of. 
This can be done by heating it, when it passes off in 
the form of vapor, just as water does, and then what- 
ever is in solution will remain behind. For this pur- 
pose put the solution in a small, clean porcelain 
evaporating-dish, and put this on a vessel containing 
boiling water, or a water-bath. The operation should 
be carried on in a place where there is a good draught, 
so that the vapors will not collect in the working-room. 
They are not poisonous, but they are annoying. The 
arrangement for evaporating is iulustrated in Fig. 2. 

5. After the liquid has evaporated and the substance 
in the evaporating-dish is dry, examine it and care- 
fully compare its properties with those of the sub- 
stance which was put into the test-tube. 

Is it the same substance? 

Is it hard or soft? 

Does it change when heated in a tube? 

Is there an appearance of bubbling when hydro- 
chloric acid is poured on it ? 

Does it dissolve in water ? 


Does it change when allowed to lie in contact with 
the air? 





CONTACT AND CHEMICAL CHANGE, 


EXPERIMENT 4. 
Test-tube; bit of copper; nitric acid; evaporating-dish; water-bath. 


1. Bring together in a test-tube a bit of copper, 
half the size of a ten-cent piece, and 30 to 40 drops of 
nitric acid.* Hold the mouth of the tube away from 
your face and do not inhale the vapors. 

What is the appearance of the vapors given off ? 

What is the appearance of the liquid in the tube ? 

Does the copper dissolve ? 

If it does not dissolve completely add a few drops 
more of the acid. Wait until no more action takes 
place, and if necessary add a few drops more of the 
acid. : 

2. Examine the solution, as in the preceding experi- 
ment, and see what has been formed. 

What are the properties of the substance found 
after the liquid has evaporated ? 

Is it colored ? 

Is it hard or soft? 

Does it change when heated in a tube? 

Is it soluble in water ? 

Does it in any way suggest the copper with which 
you started ? 


* The acid obtained from the dealers is concentrated. For ordinary 
use this should be ditwted by mixing it with four times its bulk of 
rain-water or distilled water. Keep two bottles, one containing 
concentrated acid, the other containing dilute acid. In this experi- 

ment use moderately dilute acid. 





CONTACT AND CHEMICAL CHANGE. 


EXPERIMENT 5. 


Dilute sulphuric acid; bit of granulated zinc; evaporating-dish; 
water-bath. 


1. Try the action of dilute sulphuric acid on zine 
in a test-tube.* An invisible gas will be given off. 
Hold the thumb loosely over the mouth of the tube, 
and after a few moments apply a lighted match to the 
mouth of the tube. 

What takes place? | 

2. After the zinc has disappeared evaporate the 
solution as before. Carefully compare the properties 
of the substance left behind with those of zine. 

What differences do you find between them ? 


*JIn experiments made in test-tubes the quantities to be used are 
always small. In this experiment, for example, use one or two 
pieces of granulated zinc of such size that they can conveniently be 
put in the tube. Then add enough dilute sulphuric acid to cover 
the zinc. The liquid should form a layer from one to two inches in 
height. 

The sulphuric acid obtained from the dealers is concentrated. 
Prepare enough dilute acid to fill, say, a 4-oz. bottle, by pouring the 
concentrated acid slowly into four times its bulk of water. Label the 
bottle dilute sulphuric acid. Use this in Experiment 5. 

To dilute ordinary concentrated sulphuric acid with water, the 
acid should be poured slowly into the water while the mixture is 
constantly stirred. If the water is poured into the acid, the heat 
evolved at the places where the two liquids come in contact with each 
other.may be so great as to convert the water into steam and cause the 
strong acid to spatter. 


HEAT AND CHEMICAL CHANGE. 


EXPERIMENT 6. 
Strip of magnesium ribbon ; sheet of paper. 


Hold the end of a piece of magnesium ribbon about 
eight inches long in a flame until it tukes fire. Then 
hold it over a sheet of. paper, so that the lheht, white , 
substance which is formed may fall upon the paper. 
If the papewis dank the prow. can jhe seen more 
easily. 

What are the properties of My substance formed ? 
In what way does it differ from magnesium ? 


CONTACT AND CHEMICAL CHANGE. 


EXPERIMENT 7. 


Dry flask of 4-oz. capacity; bit of granulated tin or of pure tin-foil; 
concentrated nitric acid. 

In a small dry flask of about four ounces capacity 
put a bit of granulated tin or of pure tin-foil. Pour 
upon it enough concentrated nitric acid to cover it. 
If no change takes place at first, heat gently. 

What evidence have you that change is taking place ? 

Is there anything in this experiment which suggests 
Experiment 4 ? 

What is left behind after the aohon is finished ? 

Compare the properties of the product with those 
of tin. 





SOLUTION AIDS CHEMICAL ACTION. 


' EXPERIMENT 8. 
Dry tartaric acid ; dry sodium bicarbonate ; test-tubes. 


1. Mix together in a dry mortar about a gram of 
dry tartaric acid and about an equal quantity of dry 
bicarbonate of soda (sodium bicarbonate). 

Do you see any evidence of action ? 

2. Now dissolve about a gram of tartaric acid in 4-5 
cubic centimeters * of water in a test-tube, and about 
the same quantity of bicarbonate of soda in water in 
another test-tube. Pour the two solutions together. 

What evidence have you now that action takes place ? 

3. Pour water upon the dry mixture first made. 

Does action take place ? 

What causes the bubbling ? 

Will a match burn in the gas? 

In which experiment already performed was a similar 
gas obtained ? 


* With the aid of the graduated cylinder, learn to judge as nearly 
as possible the volume of 1, 2, 3, 4, 5, etc., cubic centimeters. 
Pp 





SOLUTION AIDS CHEMICAL ACTION. 


EXPERIMENT 9. 


Small dry mortar; dry iron sulphate (green vitriol) ; dry potas- 
sium ferricyanide (red prussiate of potash). 

1. Mix tegether in a dry mortar about a gram of 
dry sulphate of iron (green vitriol) and about a gram 
of dry ferricyanide of potassium (red prussiate of 
potash). 

Does action take place ? 

2. Make a solution of each of the two substances 
and pour them together in a test-tube.* 

What evidence have you that action takes place ? 

3. Pour water on the dry mixture. 

Does action take place ? 


* Use about the same quantities of the substances as directed in 
Experiment 8. 





MECHANICAL MIXTURE. 


EXPERIMENT 10. 
Powdered roll-sulphur; fine iron filings ; magnifying-glass or 
small microscope ; small magnet. 

1. Mix two or three grams of powdered roll-sulphur 
and an equal weight of very fine iron filings in a small 
dry mortar. Examine a little of the mixture with a 
microscope or a magnifying-glass. 

Can you distinguish the particles of sulphur and 
those of iron ? 

2. Pass a small magnet over the mixture. 

Are particles of iron drawn out of the mixture? 

Has chemical action taken place ? 





MECHANICAL MIXTURE. 


EXPERIMENT 11. 


Bisulphide of carbon; powdered roll-sulphur ; dry test-tube ; iron 
filings; good-sized watch-glass. 


1. Pour two or three cubic centimeters of bisulphide 
of carbon* on about a gram of powdered roll-sulphur 
in a dry test-tube. 

Does the sulphur dissolve ? 

2. Treat iron filings in the same way. 

Does the iron dissolve? 

3. Now treat about half of the mixture prepared in 
Experiment 10 with three or four times its bulk of 
bisulphide of carbon. After the sulphur is dissolved 
pour off the solution in a good-sized watch-glass and 
let it stand. Examine what is left in the test-tube. 

Is it iron ? 

4, After the liquid has evaporated examine what is 
left on the watch-glass. 

Is it sulphur? 


* Caution! Carbon bisulphide or bisulphide of carbon takes fire 
easily. In working with it keep away from flames. 





A MECHANICAL MIXTURE CONVERTED INTO 
A CHEMICAL COMPOUND BY HEAT. 


‘EXPERIMENT 12. 

Powdered roll-sulphur ; filings of wrought-iron or powdered iron; — 

dry test-tube ; small dry mortar; magnifying-glass ; carbon 
bisulphide ; magnet. 

1. Mix three grams of finely powdered roll-sulphur 
with the same weight of fine wrought-iron filings or 
powdered iron to be had of the druggist. Put the 
mixture in a dry test-tube. Heat gently and note the 
changes. 

At first the sulphur melts, and may even take fire. 
But soon the mass begins to glow, and if you take the 
tube out of the flame the mass will continue to glow. 
This will soon stop; the mass will grow dark and soon 
cool down. | 

2. After the action is over and the tube has cooled 
down, break it and put the contents in a small dry 
mortar. 

Does the mass look like the mixture of sulphur and 
iron with which you started ? 

3. Examine with a microscope or magnifying-glass ; 
with carbon bisulphide; with a magnet. 

Compare your observations with those made on the 
mixture used in the preceding experiment. 

Treat a little of the substance with dilute sulphuric 
acid. Also test a little of the original mixture of iron 
and sulphur with dilute sulphuric acid. 

Notice the odor. What difference do you observe 
between the two cases ? J 

What conclusions does this experiment lead you to? 









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CHEMISTRY OF THE AIR. 


EXPERIMENT 13. 


Small porcelain crucible; tripod ; triangle; bit of lead. 


1. Inasmall porcelain crucible arranged as shown 
in Fig. 3 put a bit of lead the size of a ten-cent piece. 
Heat by means of a laboratory burner, 
and notice the changes which take 
place. After the lead has melted stir 
with a thick iron wire while heating. 
Continue to heat and stir until the 
substance is no longer liquid. 

What is its appearance now? 

2. Let it cool. 

Is it lead ? 

What difference is there between the action in this 
case and in the case of melting ice and cooling the 
water down again ? 

Which is chemical action and which physical action? 

Why? 





EXPERIMENT 14, 
Small porcelain crucible ; tripod ; triangle ; bit of zinc. 


Heat a piece of zinc in the same way as you heated 
lead in the last experiment. 
What changes take place? 


EXPERIMENT 15, 
Small porcelain crucible ; tripod ; triangle; bit of tin. 
Heat a piece of tin in the same way as the metals 


were heated in the last two experiments. 
What changes take place? 





CHEMISTRY OF THE AIR. 


EXPERIMENT 16. 


Same as for Experiments 18, 14, and 15; together with some 
borax. 


Repeat Experiments 13, 14, and 15, adding in each 
case enough borax to form a complete cover to the 
metal after the borax and the metal are melted. Do 
not stir the substances. 

Do the metals melt ? 

Are they changed to powders? 

How do you explain the difference ? 





CHEMISTRY OF THE AIR. 


EXPERIMENT 17. 


Large flat cork; bit of candle ; vessel with water; bell-jar or 
wide-mouthed bottle ; ground-glass plate. 


1. Fix a bit of candle an inch or two in length on a 
large flat cork or a block of wood. Light the candle 
and place it with the block on water contained in a 
pail or some other appropriate vessel. Place over it a 
good-sized glass vessel, either a wide-mouthed bottle 
or a fruit-jar, as represented in Fig. 4, so that the 




















candle and cork are in the glass vessel and the mouth 
of the vessel is beneath the surface of the water. 
Hold it in this position for a few minutes and observe 
what takes place. 

Does the candle continue to burn ? 

Is all the air contained in the vessel used up when 
the candle goes out? 


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EXPERIMENT 17—( Continued). 


2. Try the experiment a second time, and when the 
candle is nearly out raise the glass vessel so that air 
can get in. 

Does this make any difference ? 

What difference ? 

What do these experiments prove ? 


EXPERIMENT 18. 


Same apparatus as in Experiment 17; candle on wire, or splinter 
, of wood. 


After the candle has gone out place your hand on a 
eround-glass plate over the mouth of the vessel under 
water, and turn the vessel mouth upwards. Insert 





into it a lighted candle on a wire ora lighted splinter 
of wood as shown in Fig. 5. ? 
Is the gas contained in the vessel ordinary air ? 
How do you know? 





OXYGEN. 


EXPERIMENT 18b.* 


Hard-glass tube arranged as shown in Fig.7; small glass tube 
bent as shown in Fig. 7; 2 or 3 grams of mercuric oxide ; 
test-tubes; pneumatic trough. 


1. Heat two or three grams of mercuric oxide (red 
oxide of mercury) in a hard-glass tube arranged as 
shown in Fig.7. The tube should be fitted with a 
good cork with one hole in it through which passes a 
small glass tube. The end of this smaller glass tube 
should be bent slightly upward as shown. 

What changes take place ? 






































2. Collect some of the gas in test-tubes, and by 
means of a small stick with a spark on it determine 
whether the gas is ordinary air or not. 

Compare this experiment with Experiment 2. 

What have you learned from this experiment that 
you did not learn from Experiment 2? 


* It was by means of this experiment that oxygen was discovered 
by Priestley and Scheele in 1774. The discovery was one of the 
’ highest importance for chemistry. 





OXYGEN. 


EXPERIMENT 20. 


Flask of 100 ¢.c. capacity; rubber stopper; bent glass tube; pneu- 
matic trough; cylinders or test-tubes; 2 or 3 grams potassium 
chlorate. 


1. Arrange an apparatus as shown in Fig. 8. A 





Fia. 8. 


represents a retort of about 100 cubic centimeters 
capacity. Bis a piece of rubber tubing which is in 
turn connected with a piece of glass tubing bent up- 
ward slightly at the end which is placed under the 
surface of the water in C. 


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EXPERIMENT 20—( Continued). 


2. In A put 2 or 3 grams* (about a sixteenth of an 
ounce) of potassium chlorate, and gently heat by 
means of a lamp. Notice carefully what takes place. 

3. When gas comes off freely bring the inverted 
cylinder # filled with water over the end D of the tube, 
and let the bubbles of gas rise in the cylinder. 

4, In order to examine the gas remove the vessel 
containing it from the water, first placing over its 
mouth a glass plate, and then inverting it. 

Insert into it a stick with a spark on its end. 

What takes place ? 

Is the gas contained in the vessel ordinary air ? 

What caused the chemical change in this case? 

In what respects is this chemical change like that 
in the last experiment ? 


. 


* A smaller quantity of potassium chlorate may be used in a test- 
tube arranged as in Fig, 7. 





OXYGEN. 


EXPERIMENT 21. 


10 grams potassium chlorate ; same weight of coarsely powdered 
manganese dioxide ;: glass retort ; cylinders ; bottles. 


Mix 10 grams (or about a quarter of an ounce) of 
potassium chlorate with an equal weight of coarsely 
powdered manganese dioxide* in a mortar. Heat the 
mixture in a glass retort + arranged as shown in Fig. 8, 
and collect the gas by displacement of water in ap- 
propriate vessels—cylinders, bell-glasses, bottles with 
wide mouths, etc., using as many as may be neces- 
sary to hold the gas given off. 


* Black oxide of manganese is sometimes adulterated with other 
substances, and when heated with potassium chlorate it may then 
give rise to explosions. It should be tested before using by mixing 
about half a gram of it with an equal weight of potassium ‘chlorate 
and heating ina dry test-tube. Ifthe decomposition takes place 
‘quietly the substance may be used for the preparation of oxygen. 

+ Instead of a retort a good-sized test-tube may beused. Arrange 
as in Fig. 7, 


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OXYGEN. 


EXPERIMENT 22. 


Vessels filled with oxygen ; deflagrating-spoon ; sulphur; char- 
coal; bit of phosphorus. 


Turn three of the bottles containing oxygen with 
the mouth upward, leaving them covered with glass 
plates. Into one introduce a little sulphur in a so- 
called deflagrating-spoon, which is a small cup of iron 
or brass attached to a stout wire which passes through 
a round metal plate,* usually of tin (see Fig. 9). In 
another put a little charcoal (carbon), and in a third 
a piece of phosphorust about the size of a pea. Let 
them stand quietly and notice what changes, if any, 
take place. : 

Does oxygen at ordinary temperatures act readily 
upon the substances used in the experiments ? 


* Such plates can be had of the dealers. One that will answer the 
purpose can be made by punching a small hole through the centre 
of the cover of a blacking-box. Force the handle of the spoon 
through the hole so that it is held firmly in place. 

+ Phosphorus should be handled with great care. It is always 
kept under water, usually in the form of sticks. When a piece is 
wanted, take out a stick with a pair of forceps, and put it under 
water in an evaporating-dish. While it 1s under the water cut off a 
piece the size wanted. Take this out by means of a pair of forceps, — 
lay it for a moment on a piece of filter-paper, which will absorb most 
of the water ; then quickly put it in the spoon. 






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OXYGEN. 


EXPERIMENT 23. 
Same apparatus as for Experiment 22 ; sulphur. 


1. In adeflagrating-spoon set fire to a little sulphur* 
and let it burninthe air. Notice 
whether it burns with ease or with 
difficulty. Notice the odor of the 
fumes which are given off. 

2. Now set fire to another small 
, portion and introduce it in the 
spoon into one of the vessels con- 
taining oxygen, as shown in Fig. 9. 

Does the sulphur burn more 
readily in the oxygen or in the air? 

3. Notice the odor of the fumes given off. 

Does it appear to be the same as that given off when 
the burning takes place in the air ? 








EXPERIMENT 24. 
Same apparatus as for Experiment 22; charcoal. 


Perform similar experiments with charcoal. 
What takes place ? : 
Explain all that you have seen. 


* Half fill the spoon, 





OXYGEN. 


EXPERIMENT 25.* 
Same apparatus as for Experiment 22 ; phosphorus. 


Burn a small piece of phosphorus in the air and in 
oxygen. In the latter case the light emitted from the 
burning phosphorus is so intense that it is painful to 
some eyes to look at it. After the burning is over let 
the vessel stand. 

Does it become clear ? 

What has taken place ? 


* Tt may be as well for the teacher to perform this experiment. It 
is simple enough, but phosphorus is a dangerous substance, and the 
burns caused by it heal with difficulty. The piece of phosphorus 
burned should be about the size of a small pea. It should be put on 
the deflagrating-spoon, and this should be fixed in the middle of a 
rather large glass vessel containing oxygen. 





OXYGEN. 


EXPERIMENT 26, 
Old watch-spring (see foot-note), or iron picture-wire. 


Straighten a steel watch-spring * and fasten it in a 
piece of metal, such as is used for fixing a deflagrating- 
spoon in an upright position; wind a little thread 
around the lower end, and dip it in melted sulphur. 
Set fire to the sulphur, and insert the spring into a 
vessel containing oxygen. 

Instead of the spring iron picture-wire may be used. 

It is only necessary to heat the end and dip it into 
powdered sulphur before putting it into the vessel 
containing the oxygen. 

Describe all that takes place. 

When iron is exposed to the air what is the color of 
the substance formed on its surface ? . 

Does this substance suggest anything formed in the 
experiment ? | 

How do you explain the resemblance ? 


* Old watch-springs can generally be had of any watchmaker or 
mender for the asking. A spring can be straightened by unrolling 
it, attaching a weight, and suspending the weight by the spring. 
The spring is then heated up and down to redness with the flame of 
a laboratory burner or spirit-lamp, 





NITROGEN. 


EXPERIMENT 27. 


Wide-mouthed jar such as used in Experiment 17 ; small porce- 
lain crucible fastened on a flat cork; bit of candle; trough: 
sulphur. 


1. Place a wide-mouthed jar over water in a larger 
vessel of water. In the middle of a flat cork about 
three inches in diameter fasten a small porcelain cru- 
cible, and float this on the water in the trough. Put 
in it a piece of phosphorus about twice the size of a 
' pea, and set fire to the phosphorus. Quickly place 
the jar over it on a support which will prevent the jar 
from sinking more than an inch or two in the water. 

Why is air at first forced out of the vessel ? 

Why does the water afterward rise in the vessel ? 

After the burning has stopped and the vessel has 
cooled down, about what proportion of the air is left 
in the vessel ? 

2. Cover the mouth of the jar with a glass plate 
and turn it mouth upward. Try the effect of intro- 
ducing one after the other several burning bodies into 
the gas, as, for example, a candle, a piece of sulphur, 
etc. 

Explain all that you have seen. 





WATER. 


EXPERIMENT 28. 
Dry test-tube ; bit of wood ; bit of fresh meat. 


1. Ina dry test-tube heat gently a small piece of 
wood. . 

What evidence do you obtain that water is given off ? 

2. Do the same thing with a piece of fresh meat. 

Is water formed in this case ? 


CRYSTALS AND WATER OF CRYSTAL- 
LIZATION. 


Most substances which dissolve in water are more 
soluble in hot water than in cold. In a hot solution 
there may therefore be more of a substance than can 
remain in solution when cool. On cooling, the sub- 
stance will in many cases be deposited in regular- 
shaped masses which are called crystals. 


EXPERIMENT 29. 
6 to 8 oz. ordinary alum; funnel and plaited filter ; filter-paper ; 
dry test-tube. 

1. Dissolve some ordinary alum in water (6-8 ounces 
alum to 200 cubic centimeters of water) by the aid of 
heat. Filter through a plaited filter and allow the 
filtered solution to cool. 

What takes place ? 

2. Pour off the liquid above and place a few of the 
crystals on a piece of dry filter-paper.. After the 
water is all absorbed from them and they appear dry, 
put them in a dry test-tube and heat gently. 

What evidence have you that water is contained in 
the crystals ? 





WATER OF CRYSTALLIZATION. 


EXPERIMENT 30. 
Piece of gypsum; dry test-tube. 


In a dry test-tube heat a piece of gypsum the size of 
a small marble. Gypsum is the natural substance 
from which “ plaster of Paris ” is made. 

What evidence have you that water is contained in 
this substance ? 

What is the appearance of the substance which is 
left behind after the heating ? 

Does it resemble the original piece of gypsum ? 


EXPERIMENT 31. 


Few small crystals of copper sulphate ; dry test-tube ; test-tube; ~ 
evaporating-dish or small beaker. 

1. Heat gently a few small crystals of copper sul- 
phate (“blue vitriol’’) in a dry test-tube. 

What change besides the escape of water do you 
notice ? 

What is the color of the powder which is left be- 
hind ? 7 

2. Dissolve this powder in a little water in a test- 
tube. 

What is the color of this solution ? 

3. Evaporate off some of the water and let the so- 
lution cool. Repeat this, if necessary, until on cool- 
ing crystals are deposited. 

What is the color of the crystals ? 

Do these crystals in any way suggest those with 
which you started ? 


aig.dits 





EFFLORESCENT COMPOUNDS. 


' EXPERIMENT 32. 
Crystals of sodium sulphate and of sodium carbonate; watch-glass. 


Selecta few crystals of sodium sulphate or Glau- 
ber’s salt which have not lost their lustre. Put them 
on a watch-glass, and let them lie exposed to the air 
for an hour or two. 

What evidence have you that change takes place ? 

Perform a similar experiment with a few clear crys- 
tals of sodium carbonate (sal soda or washing soda). 

Is there any evidence of change in this case ? 


DELIQUESCENT COMPOUNDS. 


EXPERIMENT 33. 
Calcium chloride ; watch-glass. 


Expose a few pieces (the size of a pea) of calcium 
chloride to the air. Calcium chloride was the product 
obtained in Experiment 3. If there is none in the 
laboratory, make some. 

What change takes place when the substance is ex- 
posed for some time to the air? 





DECOMPOSITION OF WATER. 


EXPERIMENT 35. 


Sodium ; battery-jar or large beaker with water ; piece of card- 
board. 

Throw a small piece of sodium* on water contained 
in a battery-jar or large beaker. Cover the vessel 
with a piece of cardboard. While it is floating on the 
surface apply a lighted match to it. 

What takes place ? 

What causes the flame ? 

Why is the flame yellow ? 


* The metals sodium and potassium are kept under kerosene oil. 
When a small piece is wanted, take out one of the larger pieces 
from the bottle, roughly wipe off the oil with filter-paper, and cut 
-off a piece the size needed. It is not advisable to use a piece larger 
than a small pea. Dry your fingers before handivng these metals. 


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HYDROGEN. 


EXPERIMENT 37. 


Granulated zinc; ordinary hydrochloric acid ; cylinder or test- 
tube ; dilute sulphuric acid. 


1. In a cylinder or test-tube put a few pieces of 
granulated zinc, and pour upon it enough ordinary hy- 
drochloric acid to cover it. 

What do you notice ? 

2. After the action has continued for a minute or 
two, apply a lighted match to the mouth of the 
vessel. 

What takes place ? | 

3. Try the same experiments using sulphuric acid 
which has been diluted with four times its volume of 
water.* 

What is the result ? 

What is the gas given off? 


* See note, Experiment 5. 


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HYDROGEN. 
EXPERIMENT 37 *—( Continued). 
Woulff's flask (Fig. 10) or wide-mouthed bottle (Fig. 11); granulated 
zinc ; dilute sulphuric acid ; cylinders and bottles. 

For the purpose of collecting hydrogen the gas 
should be evolved from a bottle with two necks called 
a Woulff’s flask (see Fig. 10), or a wide-mouthed bottle 
in which is fitted a cork with two holes (see Fig. 11). 





Fia. 10. Fia. 11. 
Put a small handful of granulated zine f into the 


* Always be cautious when working with hydrogen. The danger 
lies in the fact that a mixture of hydrogen and oxygen, or of 
hydrogen and air, explodes violently when a spark or flame comes in 
contact with it. Always let the gas escape for a time, from 3 to 5 
minutes, or longer if the acid acts slowly upon the zinc, and then, 
before applying a flame to the gas issuing from the generating vessel, 
fill a test-tube by displacement of water, and light it to see whether 
it will burn quietly without explosion. If it will not, wait longer. | 

t Some zinc, particularly that which is pure, does not act readily 
upon acids. Whether the action is taking place freely or not can be 
seen by the effervescence in the flask and by the rate at which bubbles. 


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EXPERIMENT 37—( Continued). 


bottle and pour upon it enough cooled dilute sulphuric 
acid (1 volume concentrated acid to 4 volumes of water) 
to cover it. Collect by displacement of water as in 
the case of oxygen. Should the action become slow 
add a little more of the dilute acid. Fill four or five 
cylinders and bottles with the gas. 


EXPERIMENT 38. 

Pass some of the gas through a solution of potas- 
sium permanganate. Collect some of it, and notice 
whether it has an odor. 

Arrange the apparatus as shown in Fig. 12. The 
solution of potassium permanganate is contained in 
the small cylinder A, and the tubes are so arranged 
that the gas bubbles through it. 





Fria. 12. 


of gas appear at the end of the delivery-tube when this is placed under 
water. If the action is slow, wait longer before collecting it and before 
setting fire to it. It is better not to use zinc which acts slowly. 








HYDROGEN. 


EXPERIMENT 39.*- 


Place a vessel containing hydrogen with the mouth 


upward and uncovered. In a short time examine the 


gas and see whether it is hydrogen. 


EXPERIMENT 40. 

Cylinder of hydrogen ; empty cylinder. 
Gradually bring a vessel containing hydrogen with 
its mouth upward below 
an inverted vessel contain- 
ing air, in the way shown 
in Fig. 13. 

fs there hydrogen in the 

vessel with the mouth up- 

FiG. 13, ward ? 
Is there hydrogen in the other vessel ? 





EXPERIMENT 41. 
Soap; clay pipe; hydrogen generator. 

Soap-bubbles filled with hydrogen rise in the air. 
The experiment is best performed by connecting an 
ordinary clay pipe t by means of a piece of rubber 
tubing with the exit-tube of a flask in which hydrogen 
is being generated. Small balloons of collodion are 
also made for showing the lightness of hydrogen. 
Large balloons are always filled with hydrogen or 
some other light gas. Some kinds of illuminating-gas 
are rich in hydrogen, and may therefore be used for 
the purpose. 

*In all experiments with hydrogen see that no flames are burning 
hear you, 


+ It is best to wet the pipe thoroughly to prevent the loss of hy- 
drogen by diffusion. 








HYDROGEN. 


EXPERIMENT 42. 


Hydrogen generator ; platinum tube; glass tube. 


Roll up a small piece of platinum-foil, 
or take a small platinum tube, and fuse it 
into the end of a glass tube as shown 
in Fig. 14. 

Connect the burner thus made with a 
hydrogen generator and light the gas. 
Is the flame colored or colorless ? 

Hold a piece of wire in it. Is it 
hot? 





EXPERIMENT 48. 


Taper fastened on wire ; cylinder full of hydrogen. 


1. Hold a wide-mouthed bottle or cylinder filled 
with hydrogen with the mouth down- 
ward. Insert into the vessel a lighted 
taper held on a bent wire, as shown in 
Fig. 15. 

What do you observe ? 

What burns ? 

Does the taper continue to burn? 

2. Withdraw the taper and hold the 
wick for a moment in the flame at the 
mouth of the cylinder, then withdraw 
it entirely. Put it back again in the 
hydrogen. 

Does hydrogen support combustion ? 

Does it burn ? Fia. 15. 

3. Try similar experiments with a piece of wood. 








AMMONIA. 


EXPERIMENT 50. 


Ammonium chloride ; watch-glass ; caustic soda ; caustic potash ; 
quicklime. 


1. To alittle* ammonium chloride on a watch-glass 
add a few drops of a strong solution of caustic soda, 
and notice the odor of the gas given off. 

2. Do the same thing with caustic potash. 

3. Mix a gram of quicklime and a gram of ammo- 
nium chloride in a mortar, and notice the odor. 

Has ammonium chloride this odor ? 

What is the substance with the odor? 

How is it formed in the experiments ? 


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AMMONIA. 


EXPERIMENT 51. 


Apparatus shown in Fig. 16; 100 grams quicklime; 50 grams 
ammonium chloride; sand-bath; dry cylinder or bottle, 
Fig. 17; taper on wire. 


1. Arrange an apparatus as shown in Fig. 16, omit- 





Fia. 16. 


ting, however, the funnel-tube. In the flask put 100 
grams of quicklime and add just enough water to slake 
it without making it moist; then add 50 grams ammo- 
nium chloride and mix by shaking. Push the stopper 
into place and gently heat on a sand-bath.* The 
Woulff’s flasks are one-third filled with water, and the 
tubes so arranged that the gas given off from the 
generating flask must pass down nearly to the surface 
of the water, but not bubble through it. 

After the air is driven out the gas will be completely 
absorbed by the water in the first flask. 

2. After a short time disconnect at A, and connect 
with another tube bent upward. Collect a cylinder 








*A sand-bath is a shallow vessel of sheet-iron or tin-ware contain- 
ing a layer of dry and fine sand, 


—L eS 





EXPERIMENT 51—( Continued.) 


or bottle full of the escaping gas by displacing air, 
placing the vessel with the mouth downward, as the gas 
is much lighter than air. The arrangement is shown 
in Fig. 17. The tube through which the gas enters 
the vessel should pass through a piece of thick paper 
or of card-board, and this should rest 
against the mouth of the vessel. The 
object of this is to prevent currents of 
air from carrying the gas out of the 
vessel. You can determine when the 
vessel is full of gas by the strong 
smell of the gas. Jn working with the 
gas great care must be taken to avoid 
breathing it mn any quantity. The vessel 
in which the gas is collected should 
be dry, as water absorbs ammonia very readily. 
Hence also, the gas cannot be collected over water. 

8. As soon as the cylinder or bottle is full of gas, 
connect the delivery-tube again with the series of 
Woulff’s flasks, and pass the gas over the water as 
long as it is given off. Save this liquid and label it 
ammonia. It is this solution which is used under the 
name ammonia in the laboratory. 

4. In the gas which you have collected introduce 
a burning stick or taper. 

Does the gas burn? 

Does it support combustion ? 

















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NITRIC ACID. 


EXPERIMENT 52. 


Apparatus shown in Fig. 18 ; 25 grams sodium nitrate; 15 grams 


concentrated sulphuric acid. 


Arrange an apparatus as shown in Fig. 18. In the 


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Fie. 18. 





retort* put 25 grams sodium nitrate (Chili saltpetre) 
and 15 grams concentrated sulphuric acid. Heat 
gently. 

What takes place ? 

What is the color due to? 

Put this liquid in a bottle and label it “‘Concen- 
trated Nitric Acid.” 


* This experiment may be simplified by using a large test-tube as a 


receiver. It can be kept cool by immersing the lower part in cold | 


water contained in an evaporating-dish or beaker, 


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NITRIC ACID. 


EXPERIMENT 55. 
Liquid obtained in last experiment: bits of tin, zinc iron, lead. 


1. In test-tubes try the action of the liquid you ob- 


tained in the last experiment on a few small pieces of’ 


cranulated tin contained in a small flask. 

Describe the results obtained. 

2. Perform similar experiments with bits of zine, 
iron, and lead. 

What results do you obtain ? 


EXPERIMENT 56. 

Copper-foil; ordinary, commercial concentrated nitric acid ; 
flask - evaporating-dish ; water-bath ; dry test-tube-; con- 
centrated sulphuric acid. 

1. Dissolve a few pieces (10-20 grams) of copper- 
foil in ordinary, commercial concentrated nitric acid 
diluted with about half its volume of water. Add the 
diluted acid gradually to the copper, so thatnot much 
more is used than is necessary to dissolve the metal. 
The operation should be carried on in a good-sized 
flask, and either out of doors or under a good hood, 

What action takes place ? 

After it is over what is the appearance of the liquid 
in the flask ? 

2. Pour it out and evaporate to crystallization. 

3. Heat two or three smail crystals in a dry test- 
tube. 

What change do you observe ? 

4. Treat three or four small crystals with four or 
five drops of concentrated sulphuric acid, and warm 
gently. 

Do you obtain any evidence that the substance is a 
nitrate ? 





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NITROUS OXIDE. 


EXPERIMENT 57. 
Retort of 3-4 oz. capacity ; 10-15 grams crystallized ammonium 


nitrate; wide rubber tube; cylinders; bottles; candle on 
wire ; bits of wood. 


In a retort heat 10 to 15 grams crystallized am- 
monium nitrate until it has the appearance of boiling. 
Do not heat higher than is necessary to secure a reg- 
ular evolution of gas. Connect a wide rubber tube 
directly with the neck of the retort, and collect two 
or three bottles full of the gas over water, as in the 
case of oxygen. 

What chemical change takes place ? 


EXPERIMENT 58. 


Cylinders of nitrous oxide; splinter of wood; candle; phos- 
phorus ; deflagrating-spoon. 
Insert into the gas obtained in the last experiment 
a piece of burning wood, a candle, and a small bit of 
phosphorus. 
Explain what takes place. 


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NITRIC OXIDE. 


EXPERIMENT 59. 


Apparatus shown in Fig. 19; copper-foil; ordinary concentrated 
nitric acid ; cylinders ; bottles. 

Arrange an apparatus as shown in Fig.19. In the 
flask put ten or twelve pieces of copper- 
foil one or two inches long by about 
half an inch wide. Cover this with 
water. Now slowly add ordinary con- 
centrated nitric acid. When enough 
acid has been added gas will be given 
off. If the acid is added quickly it not 
infrequently happens that the evolu- 
tion of gas takes place too rapidly, so 
that the liquid is forced out of the flask 
through the funnel-tube. This can be 
avoided by not being in a hurry. 

What is the color of the gas in the 
flask at first ? 

What is it after the action has con- 

Beau tinued for a short time ? 

Fill two or three vessels with the gas over water. 

Do not inhale the gas. Perform the experiments with 
nitric oxide where there 1s a good draught. 





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NITRIC OXIDE. — 


EXPERIMENT 60. 
Vessels filled with nitric oxide in last experiment ; burning candle. 


Turn one of the vessels containing colorless nitric 
oxide with the mouth upward and uncover it. 

What takes place ? 
_ Explain the appearance of the colored gas in Expert- 
ment 59, and the fact that it afterward disappeared. 

What was in the vessel at the beginning of the op- 
eration ? 


EXPERIMENT 61. 
Cylinder of nitric oxide; candle. 
Into one of the vessels containing nitric oxide insert 
a burning candle. 


Does the gas burn ? 
Does it support combustion ? 


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CHLORINE. 


EXPERIMENT 62.* 


Apparatus shown in Fig. 20; 100 grams (8 to 4 ounces) man- 
ganese dioxide; concentrated hydrochloric acid; sand-bath; 
6 or 8 dry cylinders; funnel and filter; evaporating-dish; 
water-bath. 


1. Ina flask put about 100 grams (8 to 4 ounces) 
of black oxide of manganese. Pour upon it enough 
ordinary concentrated hydrochloric 
acid to cover it completely. Arrange 
the apparatus as shown in Fig. 20. 
Heat gently in a sand-bath. 

What is given off? 

Write the equation representing the 
action. } 

2. Fill six or eight dry cylinders or 
bottles with chlorine by letting the 
WY delivery-tube extend to the bottom of 

Fia. 20. the collecting vessel and covering the 
mouth of the vessel with a piece of paper. You can 
see when the vessel is full by the color of the gas. 





*The experiments with chlorine should be carried on in a place 
where the draught is good. Do not inhale the gas. 





CHLORINE. 


EXPERIMENT 62—( Continued). 

Vessels filled with chlorine; powdered antimony; copper-foil ; 
piece of paper with writing on it; colored flowers; colored 
calico. 

3. Into one of the vessels containing chlorine intro- 
duce a little (as much as you can put on a ten-cent 
piece) finely powdered antimony. If the action does 
not take place readily, warm the antimony slightly 
before pouring it into the chlorine. 

What takes place ? 

In what respects is this experiment like the one in 
which iron was burned in oxygen ? 

4. Into a second vessel put a few pieces of copper- 
foil which you have heated. 

What takes place ? 

5. Into a third vessel put a piece of paper with 


writing on it, some flowers, and some pieces of colored 


calico which you have motstened. 

What takes place ? 

6. Into a fourth vessel put a dry piece of the same 
calico used in 5. 

What difference is there in the action of the chlorine 
on the dry and on the moist calico? 

Write a full account of the method you have used in 
preparing chlorine, and of the results obtained in the 
experiments with chlorine. 

Compare chlorine with hydrogen and with oxygen. 


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HYDROCHLORIC ACID. 


EXPERIMENT 63. 
Hydrogen generator ; cylinder of chlorine ; blue litmus * solution. 


Light a jet of hydrogen in the air and carefully 
introduce it into a cylinder of chlorine. 

Does it continue to burn? 

What is the appearance of the flame ? 

What evidence have you that a product is formed ? 

Pour a little blue litmus solution into the cylinder 
and shake. 


What do you notice? 


EXPERIMENT 64. 
Common salt ; concentrated sulphuric acid ; test-tube. 


Pour 2 or 3 cubic centimeters of concentrated sul- 


phuric acid on a gram or two of common salt in a test- 
tube. 


What takes place ? 
Is a gas given off? 
What is its appearance ? 


—_—— 


* Litmus is a vegetable substance prepared for use as a dye. 





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HYDROCHLORIC ACID. 


EXPERIMENT 65. 


Apparatus shown in Fig. 16; common salt; concentrated sul- 
phuric acid; sand-bath; dry cylinder; candle on wire; fun- 
nel and filter; evaporating-dish; water-bath ; filter-paper ; 
ignition-tube; test-tubes; iron filings; granulated zinc; man- 
ganese dioxide; blue litmus; caustic soda or ammonia. 


Arrange an apparatus as shown in Fig. 16, Exp. 51. 
Weigh out, separately, 100 grams common salt, 100 
grams concentrated sulphuric acid, and 20 grams — 
water. Mix the acid and water, taking the usual pre- 
cautions (see note, Exp. 5). Let the mixture cool 
down to the ordinary temperature, and then pour it 
on the salt in the flask. 

2. Heat the flask gently in a sand-bath. Conduct | 
the gas at first over water contained in two Woulff’s 
flasks. 

After the gas has passed for 10 to 15 minutes dis- 
connect at 4 (see Fig. 16). 

What appears? 

“ Blow your breath” on the gas coming out of the 
tube, taking care not to get too near the end of the 
tube. 

What effect has this ? 

3. Apply a lighted match to the end of the tube. 

Does the gas burn? 

Does the match continue to burn ? 

4, Collect some of the gas in a dry cylinder as in 
the case of chlorine, and then connect the generating- 
flask again with the flasks containing the water, and 
let the action continue until no more gas is given off. 

In collecting chlorine and hydrochloric acid the 





EXPERIMENT 65—( Continued). 


vessels must stand mouth upward. Are these gases 
heavier or lighter than air ? 

Has the gas any color ? 

Is it transparent ? 

Insert a burning stick or candle in the cylinder 
filled with the gas. 

Does the gas support combustion ? 

5. Express by an equation the action which takes 
place in the preparation of hydrochloric acid. 

What is left in the flask ? 

After the flask has cooled down pour water on the 
contents until it is covered 2 or 3 inches deep, and, 
when the substance is dissolved, filter and evaporate 
the solution to such a concentration that, on cooling, 
the sodium sulphate is deposited. Pour off the liquid, 
and dry the solid substance by placing it upon folds 
of filter-paper. 

6. Compare the substance with the common salt 
which you put into the flask at the beginning of the 
experiment.—Heat a small piece of each in a dry 
tube.—Treat a small piece of each in a test-tube with 
a little concentrated sulphuric acid. 

What differences do you observe between them ? 

If in the experiment you should recover all the so- 
dium sulphate formed, how much would you get? 

7. Put about 20 cubic centimeters of the liquid 
from the first Woulff’s bottle in a porcelain evaporat- 
ing-dish and heat over a small flame just to boiling. 

Is hydrochloric acid given off? 

Can all the liquid be driven off by boiling? 

8. Try the action of 8-10 cubic centimeters of the 













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EXPERIMENT 65—( Continued). 


liquid from the first Woulff’s bottle on a gram or two 
of iron filings in a test-tube. 

Is a gas given off ? 

What is it ? 

9. Add 8-10 cubic centimeters of the liquid toa 
gram or two of granulated zinc in a test-tube. 

What gas is given off? 

10. Add 8-10 cubic centimeters to a gram or two of 
manganese dioxide in a test-tube. Warm gently. 

What is given off ? 

How do you know? 

11. Add ten or twelve drops to 2 or 3 cubic centi- 
meters of water in a clean test-tube. Taste the solu- 
tion. 

How would you describe the taste ? 

12. Add a drop or two of a solution of blue litmus, 
or put into it a piece of paper colored blue with 
litmus. 

What change takes place ? 

13. To.the solution to which litmus has been added 
add a drop or two of caustic soda or ammonia. 

What change takes place? 


Write a full account of all you have done since you 
started with the sulphuric acid and common salt, and 
be sure that your account contains answers to all the 
questions which have been asked. 


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NEUTRALIZATION—FORMATION OF SALTS. 


EXPERIMENT 66. 

Two burettes and stand; beakers ; stirring-rod ; dilute solu- 
tions of sulphuric, hydrochloric, and nitric acids, and of 
potassium and sodium hydroxides ; litmus solution. 

1. Make dilute solutions of nitric, hydrochloric, and 
sulphuric acids by mixing 4 cubic centimeters of dilute 
acid, such as is used in the laboratory, with about 200 
cubic centimeters of water. Make also dilute solu- 
tions of caustic soda and 
caustic potash by dissolving 
about 1 gram of each in 200 
cubic centimeters of water. 
Keep the solutions in well- 
corked bottles. 

2. Fill one burette with 
the nitric acid solution and 
the other with caustic soda. 
Measure off a definite quan- 
tity, say 20 cubic centi- 
meters, of acid, add 2 or 3 
drops of litmus solution, 
and then cautiously add 
caustic soda from the other 
burette, stirring constantly 
until the solution just turns 
blue. When red it is acid; 
it becomes blue when it is 
alkaline. At the turning- 
point it is neutral. Note the volume of caustic soda 
used. Repeat with 15 cubic centimeters and 10 cubic 
centimeters of acid. What relation do the quantities of 
alkali bear to one another ? 








EXPERIMENT 66—(Continued). 


3. Wash out the burette containing the acid and fill 
it with hydrochloric acid. Carry out the same opera- 
tion as before. 

4, Use also sulphuric acid. 

In all these cases what is the relation between the 
quantities of alkali used with 10, 15, and 20 cubic centi- 
meters of the same acid ? 

5, Perform similar experiments, using caustic potash 
and each of the three acids in succession. 


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NEUTRALIZATION—FORMATION OF SALTS, 


EXPERIMENT 67. 


Caustic soda; hydrochloric acid ; litmus solution; evaporating- 
dish ; water-bath ; nitric acid ; ignition-tubes ; sulphuric acid. 


1. Dissolve 10 grams caustic soda in 100 cubic centi- 
meters of water. Add dilute hydrochloric acid slowly, 
examining the solution from time to time by means of 
a piece of paper colored blue with litmus. As longas 
the solution is alkaline it will cause no change in the 
color of the paper The instant it passes the point of 
neutralization it changes the color of the paper red. 
When this point is reached, evaporate the water on a 
water-bath to complete dryness and see what is left. 
Taste the substance. 

Has it an acid taste ? 

Does it suggest any familiar substance ? 

If it is common salt or sodium chloride, how ought: 
it to conduct itself when treated with sulphuric acid ? 

Does it conduct itself in this way ? 

Is the substance an alkali? Is it an acid? Is it 
neutral ? 

Write the equation representing the action. 

2. Perform the same experiment as under 1, using 
dilute nitric acid instead of hydrochloric acid.—Com- 
pare the product with sodium nitrate. 

Heati a small specimen of each in a tube closed at 
oneend. What takes place? 

Trea.t a small specimen of each with a little sul- 
phuric acid in test-tubes. What takes place? 

Writ e the equation representing the action. 
Writ ie an acceaunt of the process of neutralization. 


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EXPERIMENT 67—( Continued). 


3. Perform a similar experiment with sulphuric acid 
and caustic soda. 

What is formed? In what other experiments have 
you obtained this substance ? 

Write the equation expressing the action. 

4, Try similar experiments with caustic potash and 
nitric, hydrochloric, and sulphuric acids. 

In each case compare the product with some of the 
same substance from the laboratory bottle. 


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CHARCOAL. 


EXPERIMENT 68. 


Funnel 5 to 6 inches in diameter at mouth ; filter; bone-black ; 
solution of indigo ; ink. 

1. Make a filter of bone-black by fitting a paper 
filter into a funnel 12 to 15 mm. (5 to 6 inches) in diam- 
eter at its mouth. Half fill this with bone-black. 
- Pour a dilute solution of indigo * through the filter. 

What effect does this have on the color of the 
solution ? 

2. Do the same thing with a dilute solution of ink. 
If the color is not completely removed by one filter- 
ing, filter the solutions again. 

3. The color can also be removed from solutions by 
putting some bone-black into them and boiling for a 
time. Try this with half a liter each of the ink and 
indigo solutions used in the first part of the experi- 
ment. Use about 4 to 5 grams of bone-black in each 
case. Shake the solutions frequently while heating. 


* Prepared by treating 1-2 grams of powdered indigo for some 
time with 4-5 cubic centimeters of warm concentrated sulphuric 
acid and diluting with a liter of water. : 





CARBON. 
EXPERIMENT 70. 


Powdered copper oxide ; powdered charcoal ; apparatus shown in 
Fig. 22; lime-water ; concentrated nitric acid. 

1. Mix together 2 or 3 grams powdered copper ox- 
ide, CuO, and an equal bulk of powdered charcoal ; 
heat in a hard-glass tube to which 
is fitted an outlet tube, as shown 
|). in Fig. 22. Pass the gas which is 
given off into clear lime-water con- 
tained in a test-tube. 

Is it carbon dioxide? 

What evidence have you that 
oxygen has been extracted from 
the copper oxide? 

What is the appearance of the substance left in the 
tube ? 

Does it suggest the metal copper ? 

2. Treat a little with concentrated nitric acid. 

What should take place if the substance is metallic 
copper? (See Experiment 56.) 

What does take place? 

What is the reaction which takes place between the 
copper oxide and the charcoal? Write the equation. 

Compare the action of hydrogen with that of carbon 
on copper oxide. 


In what respects are they alike, and in what respects 
do they differ ? 





Fia. 22. 


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CARBON. 


EXPERIMENT 71. 
White arsenic ; ignition-tube ; powdered charcoal. 


Perform an experiment like the last with a little 
white arsenc in a small glass tube closed at one end. 
Take about equal parts of charcoal and arsenic. 

Explain what you see. 

Compare the action in this case with that in Ex- 
periment 70. 


MARSH-GAS. 


EXPERIMENT 72. 
Fused sodium acetate; dry potassium hydroxide; quicklime; re- 
tort ; cylinders; bottles. 

Mix 5 grams fused sodium acetate, 5 grams potas- 
sium hydroxide, and 7} grams quicklime. Heat ina 
retort. Collect over water as in making nitrous oxide. 

Does the gas burn? : 

Does it give light in burning ? 


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ACETYLENE, 


EXPERIMENT 73. 


Woulff’s flask ; dropping-funnel; glass tube; acetylene burner; 
calcium carbide. 
Arrange an apparatus as shown in Fig. 23. Into 
= the flask put a few pieces of calcium 
carbide. , 
Close the stop-cock in the dropping- 
ed funnel and fill the latter with water. 
Open the stop-cock slightly so that 
the water may drip very slowly upon 
the carbide in the flask. 
After the gas has escaped for some 
time light it. 
What sort of flame does it give? 
Attach an acetylene burner to the end of the outlet- 
tube and again light the gas. 
What difference do you notice? Why? 







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CARBON DIOXIDE. 


EXPERIMENT 74, 
Test-tube ; glass tube ; lime-water. - 


Blow through some lime- 
water by means of an appa- 
ratus arranged as shown in 
Fig. 24. 

What evidence have you that 
your lungs give off carbon di- 
oxide ? 

EXPERIMENT 75. 
Sodium carbonate; marble; test- 


tubes; dilute hydrochloric, sul- 
phuric, nitric, and acetic acids. 





1. Put about a gram of sodium carbonate in each 
of four test-tubes; and then add to one tube about 
4—5 cubic centimeters of dilute hydrochloric acid, to 
a second the same quantity of dilute sulphuric acid, 
to a third the same quantity of dilute nitric acid, and 
to the fourth the same quantity of dilute acetic acid. 

What takes place ? 

Is a-gas given off? 

2. Pass it through lime-water. See Exp. 70 for ex- 
planation of “ pass.” 

Is it carbon dioxide? 

3. Perform the same experiment with small pieces 
of marble. 

What gas is given off? 

What conclusions can you draw from these obser- 
vations ? . 

How can you easily detect carbon dioxide ? 





CARBON DIOXIDE. 


EXPERIMENT ‘6. 
Apparatus shown in Fig. 25; marble; ordinary hydrochloric 
acid; cylinders; bottles; candle on wire; scales. 

1. Arrange an apparatus as shown in Fig. 25. In 
the flask put some pieces of marble, and pour ordi- 
nary hydrochloric acid on it to the depth 
of about aninch. Collect the gas by dis- 
placement of air, placing the vessel with 
the mouth upward. Jill five or six cylin- 
ders or bottles with the gas. 

2. Into one introduce a lighted candle, 
and afterwards a burning stick. 

What takes place? 

3. With another proceed as if pouring 
water from it. Pour the invisible gas 
upon the flame of a burning candle. 

4. Pour some of the gas from one ves- 
sel to another, and show that it has been transferred. 

5. Balance a beaker on a good-sized scales, and 
pour carbon dioxide into it. 

Hixplain all that you have done, giving an account 
of the properties of carbon dioxide as you have ob- 
served them in the above experiments, 











CARBONATES. 


EXPERIMENT 77. 


Apparatus for making carbon dioxide as in last experiment ; 
caustic potash ; any dilute acid ; test-tube. 

1. Pass carbon dioxide into a solution of caustic 
potash (potassium hydroxide or potassium hydrate) 
until it will absorb no more. 

2. Add any dilute acid to some of the solution thus 
obtained. 

What gas is given off when the acid is added ? 

How do you know? 

Write the equations expressing the reactions which 
take place on passing the carbon dioxide into the 
caustic potash solution, and on adding an acid to the 
solution. 





CARBONATES. 


EXPERIMENT 78, 


Apparatus for carbon dioxide ; lime-water ; filter ; dilute acid. 


1. Pass carbon dioxide into 50 to 100 cubic cen- 
timeters of clear lime-water. 

2. Filter off the white insoluble substance. 

3. Try the action of a little dilute acid on it. 

What evidence have you that itis calcium carbonate? 

How could you easily distinguish between lime- 
water and a solution of caustic potash? — 


EXPERIMENT 79. 
Apparatus for carbon dioxide ; lime-water. 
1. Pass carbon dioxide first through a little water 
to wash it, and then into 50 to 100 cubic centimeters 
of clear lime-water. 


2. After the solution has become clear, heat it. 
What has taken place ? 


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CARBON MONOXIDE. 


EXPERIMENT 80. 


Flask of about 4 0z. capacity; crystallized oxalic acid; concentrated 
sulphuric acid; two Woulff’s flasks; solution of caustic soda; 
cylinders or bottles for collecting gas. 

Put 10 grams crystallized oxalic acid and 50 to 
60 grams concentrated sulphuric acid in an appro- 
priate-sized flask. Connect with two Woulffs flasks 
containing caustic-soda solution. Heat the contents 
of the flask gently. Collect some of the gas over 
water. Set fire to the same, and notice the character- 
istic blue flame. 

What is formed when the gas burns? 

Why is the gas first passed through caustic soda ? 


EXPERIMENT 81. 


Granulated copper oxide; hard-glass tube; apparatus for making 
carbon monoxide as used in last experiment; lime-water. 

Put a gram or two of copper oxide in a hard-glass 
tube. Pass carbon monoxide through the tube and 
over the copper oxide, while gently heating the tube. 

What change do you observe in the appearance of 
the copper oxide ? 

What happens when the gas is passed into lime- 
water after it has passed over the heated copper oxide? 
Why? | 

Express the chemical change by means of an equa- 
tion. 


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FLAMES. 


EXPERIMENT 82.* 
Wire gauze ; Bunsen burner. 


1. Light a Bunsen burner. Bring down upon the 
flame a piece of brass or iron-wire gauze. 

Does the flame pass through the gauze ? 

2. Apply a light above the gauze and above the 
outlet of the burner. 

Is there any gas unburned above the gauze ? 

Why does the flame not pass through the gauze? - 

3. Turn on a Bunsen burner. Do not light the 
gas. Hold a piece of wire gauze about one and a half 
to two inches above the outlet. Apply a lighted match 
above the gauze. 

Where is the flame ? 

What is below the gauze ? 

Prove it. 

What is the principle upon which the miner’s safety- 
lamp is constructed ? 

For what is it used ? 


* This experiment cannot be performed if spirit-lamps are used 
instead of gas-burners. 








BROMINE AND HYDROBROMIC ACID. 


EXPERIMENT 83. 


Test-tube ; potassium bromide; manganese dioxide; dilute 
sulphuric acid. 

Mix together about a gram of potassium bromide 
and two grams of maganese dioxide. Pour upon the 
mixture, in a good-sized test-tube, sufficient dilute 
sulphuric acid to cover it. Heat gently. 

What do you observe ? 

Perform this experiment where there is a good 
draught. 


EXPERIMENT 84. 


Test-tube ; potassium bromide; concentrated sulphuric acid ; 
potassium or sodium chloride. 

1. In a test-tube put two or three small crystals of 
potassium bromide. Pour on them a few drops of 
concentrated sulphuric acid. 

What do you see? 

2. Treat two or three crystals of potassium or sodium 
chloride in the same way. 

What difference is there between the two cases ? 

Explain the difference. 





IODINE AND HYDRIODIC ACID. 


EXPERIMENT 80. 
Test-tube ; potassium iodide ; manganese dioxide ; concentrated 
sulphuric acid. 

Mix about 1 gram potassium iodide with about twice 
its weight of manganese dioxide. Treat with 2-8 cu- 
bic centimeters of concentrated sulphuric acid in a 
test-tube. Heat gently. 

What takes place ? Explain. © 


EXPERIMENT 86. 
Iodine ; alcohol; potassium iodide ; test-tubes. 


Make solutions of iodine in water, in alcohol, and 
in a water solution of potassium iodide. In each case 
use one or two small crystals of iodine and a small 
test-tube. or the solution of potassium iodide dis- 
solve a piece the size of a pea in two or three cubic 
centimeters of water. 

Is iodine soluble in water ? 

Is it soluble in alcohol? 

Is it soluble in a solution of potassium iodide ? 


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IODINE AND HYDRIODIC ACID. 


EXPERIMENT 87. 


Starch ; iodine ; potassium iodide ; chlorine-water, made by pass- 
ing chlorine gas into water. 

1. Make some starch-paste by covering a few grains 
of starch in a porcelain evaporating-dish with cold 
water, grinding this to a paste, and pouring 200-300 
cubic centimeters of boiling water on it. 

2. After cooling add a few drops of this paste to a 
dilute water solution of iodine. 

What change takes place ? 

3. Now add a little of the paste to a dilute water 
solution of potassium iodide, prepared as in Exp. 86. 

Is there any change of color ? 

4, Add a drop or two of a solution of chlorine in 
water. 

What takes place ? 

Explain what you have seen, ; 

Does chlorine alone form a blue compound with 
_ starch ? 


EXPERIMENT 88. 


Potassium iodide; concentrated sulphuric acid. 


‘Treat a few small crystals of potassium iodide with 
concentrated sulphuric acid. 

What do you notice ? 

Compare with the results obtained when potassium 
bromide and sodium chloride are used. 





HYDROFLUORIC ACID. 


EXPERIMENT 89. 


Lead or platinum crucible; powdered fluor spar; concentrated 
sulphuric acid ; wax or paraffin. 

In a lead or platinum vessel put a few grams (5-6) 
of powdered fluor spar, and pour on it enough concen- 
trated sulphuric acid to make a thick paste. Cover 
_ the surface of a piece of glass with a thin layer of wax 
or paraffin, and through this scratch some letters or 
figures, so as to leave the glass exposed where the 
_scratches are made. Put the glass with the waxed 
side downward over the vessel containing the fluor 
spar, and let it stand for some hours. Then take off 
the glass and scrape off the coating. 

What chemical changes have taken place in this 
experiment? 

What is the change in the glass called? 

Suppose marks had been made on the glass by a 
diamond, would the change be chemical or physical? 


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SULPHUR. 


EXPERIMENT 90. 
Small retort ; roll sulphur. 


Distil about 10 grams of roll sulphur from a small 
glass retort. Do not connect with a condenser. 

Notice the changes. 

Collect the liquid sulphur which distils over ina . 
beaker containing cold water. What are its proper- 
ties ? 


EXPERIMENT 91. 
Roll sulphur ; sand crucible. 


In a covered sand or Hessian crucible melt about 
20 grams of roll sulphur. Let it cool slowly, and 
when a thin crust has formed on the surface make a 
hole through this and pour out the sulphur. The in- 
side of the crucible will be found lined with honey- 
yellow needles. 

Take out a few crystals and examine them. Are 
they brittle or elastic ? 

What is their color ? 

Are they opaque, translucent, or transparent ? 

What changes take place in the crystals when the 
crucible is laid aside a few days? 


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SULPHUR. 


EXPERIMENT 92. 
Koll sulphur; carbon bisulphide. 


Dissolve 2 to 3 grams roll sulphur in 5 to 10 cubic 
centimeters of carbon bisulphide. Put the solution 
in a small beaker, and allow the carbon bisa woe to 
evaporate by standing ¢ in the air. 

What is the appearance of the crystals? 

Are they dark yellow or bright yellow ? 

Are they brittle or elastic? 

State in tabular form the properties of the two allo- 
tropic forms of sulphur. 

What is allotropy? 


EXPERIMENT 93. 
Wide test-tube ; sulphur; copper-foil. 


In a wide test-tube heat 2-8 grams of sulphur to. 
boiling. Introduce into it small pieces of copper-foil 
or sheet-copper. Or hold a narrow piece of sheet- 
copper so that the end just dips into me boiling 
sulphur. 

What evidence have you that action takes ee 

Compare the chemical action in this case with that 
which takes place when copper-foil is put into chlorine, 





HYDROGEN SULPHIDE (SULPHURETTED 
HYDROGEN). 


EXPERIMENT 94, 


Apparatus as shown in Fig. 26; iron sulphide; dilute sulphuric 
acid ; cylinders or bottles. 








Arrange an apparatus as shown in Fig. 26. Put a 


small handful of sulphide of iron, FeS, in the flask, 


and pour cold, dilute sulphuric acid upon it. 

1. Pass the gas through a little water contained in 
the wash-cylinder A. Pass some of the gas into water. 

Is the gas soluble in water ? 

2. Collect some of the gas by displacement of air as 
in the case of chlorine and hydrochloric acid. It is 
heavier than air. ; 

3. Set fire to some of the gas contained in a cylinder. 

What products are formed ? 

Hydrochloric acid, water, ammonia, marsh gas, and 
hydrogen sulphide are all compounds of hydrogen. 
Compare them with special reference to their conduct 
towards oxygen. : 





HYDROGEN SULPHIDE. — 


EXPERIMENT 95. 


Lead nitrate; zine sulphate; arsenic trioxide (white arsenic); 
test-tubes ; dilute hydrochloric acid; apparatus for making 
hydrogen sulphide as in last experiment. 


Prepare a solution of lead. nitrate by dissolving 
about a gram in 8-10 cubic centimeters of water in a 
test-tube ; a solution of zine sulphate of the same 
strength ; and a solution of arsenic chloride by boil- 
ing about a gram of arsenic trioxide (white arsenic or 
arsenious acid) with 8-10 cubic centimeters of dilute 
hydrochloric acid in a test-tube. Pass hydrogen sul- 
phide through each solution. 

What do you observe in each case ? 


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SULPHUR DIOXIDE. 


EXERIMENT 96. 

Solution of acid sodium sulphite ; dropping-funnel ; flask of 500 
c.c. capacity ; concentrated sulphuric acid ; cylinder or bottle. 
1. Arrange an apparatus as shown in Fig. 27. A is 

a funnel-tube provided with a stop-cock. 

In the flask put a 40 per cent solution of 

acid sodium sulphite; in the funnel, after 

closing the stop-cock, put ordinary concen- 
trated sulphuric acid. Open the stop-cock 
slightly so that the acid drops into the solu- 
tion below. 

2. Pass some of the gas into a bottle 

c= —=y containing water. . 

is Is it soluble in water? 

Fia. 27. 3. Fill a vessel by displacement of air, 

(It is more than twice as heavy as air.) 

4, See whether the gas will burn or support com- 
bustion. 

Is the gas colored? Is it transparent? Has it any 
odor? Does it burn? 

In what experiment already performed was this gas 
formed ? | 









EXPERIMENT 97, 
Sulphur; porcelain crucible; bell-jar or wide-mouthed bottle ; 
tripod ; colored flowers. 

Burn a gram or two of sulphur in a porcelain cruci- 
ble under a bell-jar. Place over the crucible on a 
tripod some flowers. 

What change takes place in the flowers ? 

Compare the action with the action of chlorine. 

Does sulphur dioxide act in the same way that 
chlorine does ? 


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SULPHURIC ACID. 


EXPERIMENT 97a. 


Table-syrup ; evaporating-dish ; concentrated sulphuric acid ; 
test-tube. 

In an evaporating-dish mix 8-10 cubic centimeters 
of ordinary table-syrup and the same quantity of con- 
centrated sulphuric acid. 

The sugar which is in solution in the syrup contains 
carbon, hydrogen, and oxygen. If the sulphuric acid 
should combine with the hydrogen and oxygen, what 
would be left ? 

What is the appearance of the substance which is 
left ? 


EXPERIMENT 97b. 
Dilute sulphuric acid ; barium chloride solution. 


To 8-10 cubic centimeters of water in a test-tube 
add 4—5 drops of dilute sulphuric acid, and then add 
a few drops of a dilute solution of barium chloride, 
Bach 

Sulphuric acid can be detected by means of this 
reaction. The insoluble salt formed is barium sul- 
phate, BaSO,: : 

[H,SO, + BaCl, = BaSO, + 2HCl.] 





*'When the expression ‘‘dilute solution” is used it generally 
means a solution containing 1 part of the salt in 10-15 parts of water. 


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PHOSPHORUS. 


EXPERIMENT 98. 
Porcelain crucible or evaporating-dish; phosphorus; iodine. 


Bring together in a porcelain crucible or evaporat- 
ing-dish a piece of phosphorus about the size of a pea 
and about the same quantity of iodine. 

What takes place? 

What is the cause of the light and heat? 

Compare the action of phosphorus towards iodine 
with its action towards oxygen. 

What other examples have you had of the direct 
combination of two elements by simple contact? 

What examples have you had of direct combination 
of two elements at elevated temperature ? 





EXPERIMENT 98a. 


Disodium phosphate; ammonium chloride; ammonia; magne- 
sium sulphate; test-tube. 


To 8-10 cubic centimeters of water in a test-tube 
add 4-5 drops of a dilute solution of disodium phos- 
phate, and then add 4-5 drops of a dilute solution of 
each of the substances ammonium chloride, ammonia, 
and magnesium sulphate, MgSO,. 

Phosphoric acid can be detected by means of this 
reaction. The insoluble salt formed is ammonium 
magnesium phosphate, NH,MgPO,: 


[HNa,PO, + MgSO, + NH, = NH,MgPO,-+ Na SO,.] 


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ARSENIC. 


EXPERIMENT 99. 
Apparatus as shown in Fig. 28; granulated zinc; dilute sulphuric 


acid; granulated calcium chloride; solution of arsenic chlo- 
ride. 


Arrange an apparatus as shown in Fig. 28. The 
first horizontal tube should contain granulated cal- 
cium chloride for the purpose of drying the gases. 
The burner is not to be lighted in this experiment (see 
next exp.). Put 10-15 grams granulated zinc in the 





Fie. 28. 


flask and pour 20-30 cubic centimeters of dilute sul- 
phuric acid on it. When the air is all out of the ves- 
sel and the hydrogen is lighted, slowly add 5-10 drops 
of a solution of arsenic chloride prepared by dissolv- 
ing arsenic trioxide, As,O,, in dilute hydrochloric acid, 
as in Exp. 96. 

What change takes place in the flame? 

Is the color changed ? 

Are fumes given off? (See Exp. 100.) 





ARSENIC. 


EXPERIMENT 100. 
Apparatus used in last experiment; piece of white porcelain. 


1. Into the flame of the burning hydrogen and arsine 
produced in the last experiment introduce a piece of 
porcelain, as the bottom of a small porcelain dish or 
crucible, or a bit of a broken plate, and notice the 
appearance of the spots. . 

2. Heat by means of a Bunsen burner the tube 
through which the gas is passing, which should be of 
hard glass. 

Explain what you have seen. 


EXPERIMENT 101. 
Arsenic trioxide; finely-powdered charcoal; ignition-tube. 


Mix together about equal small quantities of arsenic 
oxide and finely-powdered charcoal. Heat the mixture 
in a small dry tube of hard glass, closed at one end. 

What change takes place ? 

What is this kind of action called ? 

What do you notice that reminds you of the preced- 
ing experiment ? 





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ANTIMONY. 


EXPERIMENT 102. 


Apparatus as shown in Fig. 28; tartar emetic; piece of white 
porcelain. 


Make some stibine, using the same kind of ap- 
paratus as that for making arsine. Instead of a solu- 
tion of arsenic use a solution of tartar emetic, which 
contains antimony. 

What differences, if any, do you notice between 
what takes place in this case and what you saw in 
Experiment 99 ? 


EXPERIMENT 103. 


Same apparatus as in preceding experiment; piece of white 
porcelain. 


Introduce a piece of porcelain in the flame and 
notice the deposit or antimony spot. 

Compare the spots with those formed with arsenic. 

Is there any difference in the appearance ? 

Heat the porcelain on which the spots are and notice 
whether any change takes place. 


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POTASSIUM. 


EXPERIMENT 104. 


Wood-ashes; filter; red litmus-paper; potassium carbonate; evap- 
orating-dish; water-bath; test-tube; dilute hydrochloric acid. 


1. Treat about a pound of wood-ashes with water. 
Filter off the solution, and examine it by means 
of red litmus-paper. 

Is the solution alkaline ? 

2, Examine some potassium carbonate. 

Does its solution act in the same way ? 

3. Evaporate to dryness the solution obtained from 
the wood-ashes. Collect the dry residue and treat it 
in a test-tube with a little dilute hydrochloric acid. 
Is a gas given off ? 

What is it? 


EXPERIMENT 105.* 


Potassium ; red litmus-paper. 


Throw a small piece of potassium not larger than 


a pea upon water. 

What takes place ? 

What is the color of the flame ? 

‘What difference is there between the action of 
sodium and of potassium on water ? 

Ts the solution after the action alkaline ? 

Why? | 


* See caution, Experiment 35, 


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POTASSIUM. 


EXPERIMENT 106. 


Crystallized potassium iodide ; iodine; test-tubes ; concentrated 
sulphuric acid. 

1. Examine a bottle of crystallized potassium iodide. 
Taste a little. Dissolve one or two of the crystals in 
water. 

2. Add one or two crystals of iodine to the solution. 
Does the iodine dissolve ? 

3. Heat one or two of the crystals. 

Does the substance contain water of crystallization ? 

4. Treat a crystal or two with a few drops of con- 
centrated sulphuric acid in a test-tube. 

What takes place ? 

To what is the appearance of violet vapors due? 
See Experiment 88. 


EXPERIMENT 106a. 


Potassium carbonate; iron sauce-pan; quicklime; stout iron wire; 
‘glass siphon. 

1. Dissolve 25 grams potassium carbonate in 250- 
300 cubic centimeters of water. Heat to boiling in an 
iron (or silver) vessel, and gradually add slaked lime 
made from 12-15 grams good quicklime. During the 
operation the mass should be stirred with a stout iron 
wire. 

2. After the solution is cool, draw it off by means 
of a glass siphon into a bottle. This may be used in 
experiments in which caustic potash is required. 

Explain what has taken place. 

Write the equation expressing the chemical change. 

What is left in the iron vessel ? 




















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POTASSIUM. 


EXPERIMENT 107. 


Potassium nitrate ; powdered charcoal. 


Mix together 15 grams finely powdered potassium 
nitrate and 2.5 grams powdered charcoal. Set fire to 
the mass. 

What is left ? 

What was given off ? 

What is gunpowder made of ? 

What is the cause of its explosive power ? 


AMMONIUM SALTS. 


EXPERIMENT 108. 


Concentrated hydrochloric acid ; concentrated ammonia ; concen- 
trated nitric ah ; sulphuric acid. 


1. Place near each other two vessels, one containing 
about 10 cubic centimeters of strong hydrochloric 
acid, and the other about 10 cubic centimeters of 
strong ammonia. 

Explain what you see. 

2. Try the same experiment using nitric acid instead 
of hydrochloric acid. 

What takes place ? 

3. Finally, try the experiment using sulphuric acid 
and ammonia. 

What difference is there between this case and the 
other two? 

How do you explain this? 





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AMMONIUM SALTS. ° 


EXPERIMENT 109. 
Piece of platinum foil or of porcelain; ammonium. chloride. 


On a piece of platinum-foil or porcelain heat a little 
ammonium chloride. 

What is the result ? 

What is the difference between this process and the 
process which we call boiling ? 

What would happen if a piece of ice were heated to 
the temperature of boiling water ? 


FLAME REACTIONS. 


EXPERIMENT 110. 


Platinum wire ; sodium carbonate ; potassium carbonate ; piece 
of blue glass. 

1. Prepare some pieces of platinum wire, 8 to 10 
em. long, with a small Joop on the end. After thor- 
oughly cleaning them, insert one into sodium carbon- 
ate, withdraw it and then notice the color it gives to 
the flame. 

2. Try another with potassium carbonate. 

3. Try a mixture of potassium carbonate and sodium 
carbonate. 

What is the color of the flame ? 

Could you tell that potassium is in the mixture by 
looking at the flame with the naked eye? 

4, Look through blue glass at the flame caused by 
potassium alone; at that caused by sodium alone; 
and at that caused by potassium and sodium. 

Can you tell whether potassium is present or not 
when you use the blue glass ? 


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POTASSIUM, SODIUM, AMMONIUM. 


EXPERIMENT 110a. 


Potassium chloride; sodium chloride; ammonium chloride ; 
chlorplatinic acid (platinum chloride). 


1. To 4-5 cubic centimeters of a dilute solution of 
potassium chloride add 5-10 drops of chlorplatinic 
acid (“platinum chloride” ), H,PtCl,. 

Potassium can be detected by means of this reac- 
tion. The difficultly soluble salt formed is potassium 
chlorplatinate, K,PtCl,. 

2. See whether platinum chloride gives a precipitate 
with a solution of a sodium salt. 

How could you distinguish between a sodium and a 
potassium salt ? 

3. Add to 45 cubic centimeters of ammonium 
chloride solution 2-8 drops of chlorplatinic acid. 

_ The precipitate formed is ammonium chlorplatinate, 
(NH,),PtCl,. 

How could you distinguish between potassium and 

sodium ? between potassium and ammonium ? 


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CALCIUM. 


EXPERIMENT 111. 


Limestone or marble; ordinary hydrochloric acid ; evaporating- 
dish; water-bath ; sulphuric acid. 


1. Dissolve 10 to 20 grams of limestone or marble 
in ordinary hydrochloric acid. Evaporate to dryness. 
Expose a few pieces of the residue to the air. 

Does it become moist? 

In what experiments has calcium chloride been 
used, and for what purposes ? 

What would happen if sulphuric acid were added 
to calcium chloride? 

2. Try it. 

Explain what takes place. 

Is the residue soluble or insoluble in water ? 

How could you tell whether a given substance is 
calcium chloride, sodium chloride, potassium chloride, 
or ammonium chloride? 

3. Try the experiment with substances the compo- 
sition of which is unknown to you. 

What happens when a solution of ammonium car- 
bonate is added to a solution of a calcium salt? 

Explain the reaction. 


. ————— ~_ 





CALCIUM. 


EXPERIMENT 112. 


Quicklime. 


1. To 40 or 50 grams good quicklime add 100 cubic 
centimeters of water. 

What takes place ? 

2. Afterwards dilute to 2 to 3 liters and put the whole 
in a well-stoppered bottle. The undissolved lime will 
settle to the bottom, and in the course of some hours 
the solution above will become clear. Carefully pour 
off some of the clear solution. : 

What takes place when some of the solution is ex- 
posed to the air? 

When the gases from the lungs are passed through 
it ? 

When carbon dioxide is passed through it ? 

What takes place when dilute sulphuric acid is 
added to lime-water ? 

Is calcium sulphate difficultly or easily soluble in 
water ? 

Has lime-water an alkaline reaction ? 

What reaction would you expect to take place be- 
tween lime and nitric acid ? 





CALCIUM. 


EXPERIMENT 113. 
Gypsum ; porcelain crucible. 


1. Heat some powdered gypsum in a porcelain 
crucible, using as small a flame as will cause water to 
be given off; or heat in an air-bath to about 180°. 

2. Examine what is left and see whether it will be- 
come solid when mixed with a little water so as to 
form a paste. 

3. See whether gypsum itself will act in the same 
way with water. 

Explain what you have done. 


EXPERIMENT 113a. 


Gypsum ; barium chloride. 


1. Make a solution of calcium sulphate by letting 
about 50 cubic centimeters of water stand in contact 
with 3-4 grams of powdered gypsum. 

The presence of a sulphate in solution can be de- 
tected by the same reaction as that used in the case 
of sulphuric acid. See Experiment 97b. 

What is this reaction ? 

2. See whether calcium sulphate is in the solution 
just prepared. 





COPPER. 


EXPERIMENT 115. 
Copper sulphate; strip of zinc; strip of sheet iron. 


1. Into a solution of 1 or 2 grams of copper sulphate 
in 15-20 cubic centimeters of water insert a strip of 
zine. 

Explain what takes place. 

Compare the action with that which takes place 
when zinc acts upon sulphuric acid. 

2. Perform a similar experiment, using a strip of 
sheet-iron instead of zinc. 

Compare this with the previous experiment. . 


EXPERIMENT 116. 
Copper sulphate; caustic soda or potash.* 


1. Add some caustic soda or potash to a small 
quantity of a cold solution of copper sulphate in a 
test-tube. 

What do you notice ? 

2. After noticing the appearance of the precipitate 

first formed, heat. 

What change takes place ? 
Explain this. 
Express the chemical change by the proper equation. 


* For test-tube experiments use a solution containing about 10 
grams of either caustic soda or potash in 100 cubic centimeters of 
water. The solution of copper sulphate is prepared by adding 5-10 
drops of such a solution as that used in Exp. 115 to 8-10 cubic cenfi- 
meters of water. 


r 


gd a, ks 5aE*) 





COPPER. 


EXPERIMENT 116a. 
Copper sulphate; hydrochloric acid; hydrogen sulphide; dilute 
nitric acid; ammonia. 

1. Prepare a dilute solution of copper sulphate (see 
note to Exp. 116), and add to it 5-10 drops of dilute 
hydrochlorie acid. 

2. Pass hydrogen sulphide through this solution for 
some time. 

The insoluble substance formed is copper sulphide, 
CuS. 

3. Filter and wash. Treat with 5-10 cubic centi- 
meters of dilute nitric acid, and then add 5-10 cubic 
centimeters of water. What isin the solution thus 
formed ? 

4. Add ammonia to 1-2 cubic centimeters of this 
solution. How could you detect copper? 





SILVER. 
EXPERIMENT 117. 
Silver coin; dilute nitric acid; common salt; filter; porcelain 
crucible; small piece of sheet zine; dilute sulphuric acid; 
evaporating-dish ; water-bath ; bottle wrapped in dark paper. 

1. Dissolve a ten or twenty-five cent piece in dilute 
nitric acid. 

What action takes place ? 

2. Dilute the solution to 200 to 800 cubic centi. 
meters with water. 

What is the color of the solution ? 

What does this indicate ? 

Does this color prove that copper is present? 

3. Add a solution of common salt (prepared by add. 
ing 100 cubic centimeters of water to 15-20 zrams of 
salt and filtering after the salt has dissolv34) until it 
ceases to produce a precipitate. 

What change takes place? 

4. Filter off the white silver chloride and carefully 
wash with hot water. | 3 

5. Dry the precipitate on the filter, by putting the 
funnel with the filter and precipitate in a warm place, 
or in an air-bath heated to 110°. 

6. Remove the precipitate from the filter and put it 
into a porcelain crucible. Heat gently with a small 
flame until the chloride is melted. 7 

7. Cut out a piece of sheet-zine large enough to 
cover the silver chloride. Lay it on the silver chloride. 
Now add 15-20 drops of water and 4-5 drops of dilute 
sulphuric acid, and let the whole stand for twenty- 
four hours. 

What takes place ? ; 

8. Take out the piece of zinc and wash the Sivan 
with a little dilute sulphuric acid, and then with 
water. 

9. Dissolve the silver in dilute nitric acid and evap- | 
orate to dryness on the water-bath, so that the excess © 
of nitric acid is driven off. Dissolve the residue in 
water, and put the solution either in a bottle of dark 
glass or one wrapped in dark panes a 








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SILVER. 


EXPERIMENT 118. 


Solution of silver nitrate prepared in last experiment; test-tubes; 
sodium chloride; potassium bromide; potassium iodide; 
ammonia. 


1. To 8-10 cubic centimeters of water in a test-tube 
add 5 to 10 drops of the solution of silver nitrate just 
prepared. 

2. To this dilute solution add a few drops of a solu- 
tion of sodium chloride. 

What takes place ? 

3. Place it aside where the light can shine upon it, 
and notice the change of color which gradually takes 
place. 

4, In the same way make the bromide by adding 
potassium bromide, and the iodide by adding potas- 
sium iodide to silver nitrate. 

What extensive practical use is made of the change 
produced in silver salts by light ? 

5. Try the effect of adding a few drops of a solution 
of ammonia to each of the test-tubes used in 4. 

What differences do you notice ? 

Given hydrochloric acid or common salt, how could 
you distinguish between a silver salt and a copper 
salt? 





IRON. 


EXPERIMENT 119. 


Iron wire; dilute hydrochloric acid; solution of sodium 
hydroxide; concentrated nitric acid. 


1. Dissolve three or four pieces of iron wire, each 
an inch or two long, in 8-10 cubic centimeters of dilute 
hydrochloric acid in a test-tube. 

What is given off? The odor is caused by other 
gases formed from impurities in the iron. 

What remains undissolved ? 

What is in solution ? 

Write the equation representing the action of the 
acid on the iron. : 

2. To four or five drops of the solution in 8-10 cubic 
centimeters of water ina test-tube add at once as 
many drops of a dilute solution of sodium hydroxide. 

What is the chemical change? 

Write the equation. 

3. Let the tube with its contents stand open, and 
shake it up from time to time. 

What changes do you notice ? 

Explain what you have seen. 

4. Prepare a dilute solution of ferrous chloride as 
in 2, and heat to boiling; then add a few drops of 
concentrated nitric acid, and boil again. Nepeat this 
two or three times. | 

What change in color takes place? 

What is now in solution ? 

5. Add four or five drops of sodium hydroxide to 
the solution. ? 

What is the chemical change? 








EXPERIMENT 119—(Continuwed). 


Compare the precipitate with that in the tube which 
you have put aside (see 3). 

6. Add a little zinc and hydrochloric acid to the 
solution of ferric chloride, and let stand until the red- 
dish-yellow color disappears. 

In what way has the ferric chloride been affected ? 
Explain. 

Add a little sodium hydroxide to some of the solu- 
tion. 


What is formed ? 


a} 


‘ 





CHROMIUM. 


EXPERIMENT 120. 


Potassium bichromate ; potassium hydroxide 7 evaporating-dish ; 
water-bath. 

To a solution of 10 to 20 grams potassium bichro- 
mate slowly add a solution of potassium hydroxide * 
until the color has turned pure yellow. Evaporate to 
crystallization. 

What is the product? Compare it with potassium 
bichromate. 

Explain the change. 


EXPERIMENT 121. 


Potassium chromate ; dilute nitric acid ; evaporating-dish ; 

water-bath. 

To the solution of the yellow salt just obtained add 
dilute nitric acid until the color has turned red. 
Evaporate to crystallization. 3 

What is the product ? 

Explain the change. 


EXPERIMENT 122. 
Potassium chromate ; potassium bichromate; hydrochloric acid ; 
test-tubes. 

Treat a gram of potassium chromate and a gram of 
potassium bichromate separately in test-tubes with 
hydrochloric acid. =~ 

Explain what takes place. 


* Prepared as recommended in foot-note to Exp. 116. 





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CHROMIUM. 


EXPERIMENT 123. 


Potassium chromate or bichromate ; barium chloride ; lead acetate 
or nitrate. 


Y 


Add a little of a solution* of potassium chromate 
or bichromate to a solution of barium chloride, and 
to a solution of lead acetate or nitrate. 


EXPERIMENT 123a. 


Barium chloride; lead acetate or nitrate ; sodium or potassium 
sulphate. 


Add a little of a solution of potassium or sodium 
sulphate to a solution of barium chloride, and to a 
solution of lead acetate or nitrate. 

How do the results compare with those obtained 
with the chromate ? 

Compare the composition of potassium chromate 
with that of potassium sulphate. 

What resemblance is there ? 


* The solutions here referred to are prepared by dissolving 1 part 
of each salt in 10-15 parts of water. Of such solutions use only 5-10 
drops in 8-10 cubic centimeters of water in a test-tube. 





EXPERIMENT 123b. 
Potassium bichromate ; dilute hydrochloric acid ; alcohol ; am- 
monia ; ammonium sulphide ; sodium hydroxide. 

1. To 5-10 cubic centimeters of a solution of potas- 
sium bichromate (see note to Exp. 123) in a test-tube 
add 10-15 drops of hydrochloric acid and 10-15 drops 
of alcohol, and boil. What change takes place ? 

[Under the conditions the chromium is changed to 
chromic chloride, CrCl,, and the potassium to potas- 
sium chloride, while some of the oxyen of the bi- 
chromate acts upon the alcohol, converting it into al- 
dehyde: 

K,Cr,O, + 8HCl = 2KCl1 + 2CrCl, + 4H,0 + 380; 
38C,H,O + 30 = 8C,H,O + 3H,0.] 
Alcohol. Aldehyde. 

2. To 10-15 drops of the solution of chromic chlo- 

ride obtained in 1 add 5-10 cubic centimeters of water, 


and then add a few drops of ammonia and of am- ~ 


monium sulphide.* 

Chromium does not form a sulphide, but, under the 
conditions named, the hydroxide, Cr(OH),, is precipi- 
tated. 

3. To a little of the dilute solution of chromic chlo- 


ride (same strength as in 2) in a test-tube add a few 


drops of a cold solution of sodium hydroxide. 
The precipitate first formed is chromic hydroxide. 
4, Add more of the solution of sodium hydroxide. 
Cr(OH), + NaOH = NaCrO, + 2H,0. 
The salt NaCrQO, is soluble in water. 
How could you detect chromium ? 
* To prepare ammonium sulphide pass hydrogen sulphide gas into 
50-100 cubic centimeters of a water solution of ammonia, as obtained 
in Exp. 51, until the gas isno longer absorbed, and then add an equa! 


volume of the same solution of ammonia. The solution has a dis. 
agreeable smell, and blackens the skin. 





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LEAD. 


EXPERIMENT 124.* | 
Lead acetate; acetic acid; wide-mouthed bottle; strip sheet-zine. 


Dissolve 6 or 8 grams lead acetate (sugar of lead) 
in a liter of water, add a few drops of acetic acid, and 
put the solution in a wide-mouthed bottle. Suspend 
a piece of sheet-zinc in the middle of the solution, and 
let it stand for a day or two. 

Describe what has taken place. 

Compare with the action of zinc on copper sulphate. 

Compare with the action of iron on sulphuric acid. 

Give the equations expressing each of the reactions 
referred to. 


* It will be best for the teacher to perform this experiment and 
then set the vessel aside. Sometimes the lead-tree formed is very 
beautiful, 





LEAD. 


EXPERIMENT 124a. 

Sheet-lead; shallow dish or plate; hydrochlorie acid; sulphurie 
acid; hydrogen sulphide; lead acetate; piece of iron; potas- 
sium ferrocyanide. 

1. Cut a piece of sheet-lead an inch or two square 
and partly cover it with water in a shallow dish. Al- 
low 1 to stand for several days, renewing the water 
from time to time. Then filter off and examine the 
water to see whether there is any lead in solution. 

(z) Lo 8-10 cubic centimeters of the water in a 
test-tube add 2-3 drops of hydrochloric acid, 

Is a precipitate formed ? 

(6) To another small portion of the water add a few 
drops of sulphuric acid. 

Is a precipitate formed ? 

(c) Into a third portion pass a little hydrogen sul- 
phide. : 

What takes place ? 

(d) 'Try the same experiments with a very dilute so- 
lution of lead acetate, prepared by dissolving a piece 
the size of a small pea in 8-10 cubic centimeters of — 
water. 

Of what practical importance is the above experi- 
ment? 

2. Try the same experiment with a piece of iron. 

_Is there any iron in solution? [The easiest way to 
find this out is to add a few drops of a solution of po- 
tassium’ ferricyanide* or red prussiate of potash, 
when, if iron is in solution, a blue color will be seen. | 


* See Experiment 9. 








LEAD. 


EXPERIMENT 125. 
Minium or red lead; dilute nitric acid. 


Treat a gram or two of minium with 8-10 cubic 
centimeters of ordinary dilute nitric acid in a test- 
tube, and note the change in color. 

Does lead pass into solution ? 

How do you know? 


EXPERIMENT 126. 


Lead peroxide; dilute hydrochloric acid. 


Treat a gram or two of lead peroxide with 8-10 
cubic centimeters of dilute hydrochloric acid in a test- 
tube. 

In what form is the lead after the experiment? 

Is the product soluble or insoluble in water? 








FERMENTATION. 
EXPERIMENT 127. 


Apparatus as shown in Fig. 29 ; commercial grape-sugar or table- 
syrup; fresh brewer’s yeast; lime-water; potassium hydroxide. 


Dissolve 150 grams commercial grape-sugar, or 150 
cubic centimeters of table syrup, in.1 to 2 liters of 
CEE . water in a flask. 
Connect the flask 
by means of a 
bent glass tube 
with a cylinder or 
bottle containing 
: Te clear lime-water. 
‘i —_-, aE The vessel con- 
F oe ai taining the lime- 
water must be 
provided with a cork with two holes. Through one 
of these passes the tube from the fermentation-flask ; 
through the other a tube connecting with a vessel con- 
taining solid caustic potash, the object of which is to 
prevent the carbon dioxide in the air from acting upon 
_ the lime-water. The arrangement of the apparatus is 
shown in Fig. 29. Now add to the solution of grape- 
sugar or syrup some fresh brewer’s yeast; close the 
connections and allow to stand. 
What changes take place? 
Explain all you have seen. 





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SOAP. 


EXPERIMENT 128. 
Small iron pot ; lard ; sodium hydroxide ; common salt. 


1. In a small iron pot boil for an hour or two a 
quarter of a pound of lard with a solution of 40 grams 
caustic soda or sodium hydroxide in 250 cubic centi- 
meters of water. After cooling add a concentrated 
solution of common salt. 

Explain what takes place. 

What is the product? 

2. Dissolve some of the product in water. 





HARD WATER. 


EXPERIMENT 129. 
Carbon dioxide generator ; lime-water; solution of soap. 


1. Make some hard water by passing carbon diox- 
ide through 200-300 cubic centimeters of lime-water 
until the precipitate first formed has dissolved again. 
Tilter. 

2. Make a solution of soap by shaking up a few 
shavings of soap with water. Filter. 

3. Add the solution of soap to the hard water. 

Is a precipitate formed ? 

4. Rub a piece of soap between the gee wet with 
the hard water. 

Explain what you observe. 


EXPERIMENT 130. 


Powdered gypsum ; solution of soap made as in last experiment. 


Make some hard water by shaking a liter or two of 
water with two or three grams of powdered gypsum. 
Perform with it the same experiments as those first 
performed with the water containing calcium car- 
bonate. 





TANNIC ACID. 


EXPERIMENT 131. 
Powdered nutgalls; ferrous sulphate. 


1. Boil 10 grams of powdered nutgalls with 60 cubic 
centimeters of water, adding water from time to time. 
A solution of tannin is thus obtained. Filter after 
standing. 

2. In a test-tube add to 8-10 cubic centimeters of 
this solution a few drops of a solution of copperas 


(ferrous sulphate). 
What is formed ? 


PREPARATION OF SOLUTIONS. 


For the work now to be done various solutions will 
be needed. The preparation of most of these has 
already been described. For the others observe the 
same general rules. In the case of a solid, dissolve 1 
part in 10 parts water, and in working with this solu- 
tion in test-tubes use only 5-10 drops diluted with 8-10 
cubic centimeters of water. In some cases it may be 
necessary to use more concentrated solutions. When- 
ever a solution, for the preparation of which the 
general rules will not suffice, is referred to after this, 
the method of preparation will be described. When- 
ever the direction is given to “add a little,” add a few 
drops of the dilute solution at first, and if, for any 
reason, it appears desirable to add more, do so, and 
note the effect. 


‘CHLORIDES. 


EXPERIMENT 132. 


1. Determine which of the chlorides are insoluble 
or difficultly soluble in water. 

This you can do by adding hydrochloric acid or a 
solutioh of some soluble chloride, as sodium chloride, 
to a solution of a soluble salt of the element you wish 
to experiment upon. Thus, for example, suppose you 
wish to know whether copper chloride is soluble or 
insoluble in water. You know that copper sulphate 
is soluble in water, as you have worked with its solu- 
tion. If copper chloride is insoluble in water, then 
on adding hydrochloric acid or a solution of sodium 
chloride to the solution of copper sulphate, a precipr- 
tate of copper chloride will be formed. 

2. In your experiments use salts of potassium, cal. 
cium, magnesium, zinc, copper, mercury (both mer- 
curic and mercurous™* salts), silver, aluminium, iron 
(both ferrous and ferric salts), manganese, chromium, 
lead, and tin. Which are the insoluble chlorides ? 

3. Try the action of sulphuric acid on several chlo- 
rides. What is given off? How do you know? 





* A solution of mercurous nitrate, HgNQs;, is prepared by treating 
asmall globule of mercury the size of a pea with 4-5 cubic centi- 


meters of dilute nitric acid. The quantity of acid should not be 


sufficient to dissolve all the mercury. Dilute the solution thus 
obtained with 5-10 times its bulk of water, 


: “ 
a 





NITRATHS. 


EXPERIMENT 133. 


1. Determine whether any of the nitrates are inso- 
luble or difficultly soluble in water. 

Work in the same way as with the chlorides. 

2. Try the action of sulphuric acid on several ni- 
trates. 

What is given off on gently warming the mixture ? 

How do you know? 

3. Heat some nitrates to a high temperature in a 
crucible. 

What takes place? 

How could you distinguish between a chloride and 
a nitrate, if both were soluble ? 


SULPHATES. 


EXPERIMENT 134. 


1. Determine which of the sulphates are insoluble 
or difficultly soluble in water. 

Which are they ? 

2. Try the action of hydrochloric and of nitric acid 
on some sulphates. 

Do you notice any change ? 

How could you distinguish between a chloride, a 
nitrate, and a sulphate ? 

See Experiments 976 and 113a. 





CARBONATES. 


EXPERIMENT 1385. 


1. Determine which of the carbonates are insoluble 
or difficultly soluble in water. After having obtained 
a precipitate, determine whether it is a carbonate or 
not by filtering, and treating the washed precipitate 
with hydrochloric acid. 

Which carbonates are difficultly soluble or insoluble 
in water? 

Which salts give, with a soluble carbonate, precipi- 
tates which are not carbonates ? 

2. Try the action of hydrochloric, of nitric, and of 
sulphuric acid on several carbonates. 

What is given off ? 

How do you know ? 


a ——- a 





SULPHIDES. 


EXPERIMENT 136. 


1. Determine with which metals hydrogen sulphide 
forms insoluble sulphides, by making solutions con- 
taining salts of the different metals, and passing hy- 
drogen sulphide through them successively. 

Which are the insoluble sulphides ? 

2. Prepare solutions of salts of the same metals 
used in 1, and add a little hydrochloric acid to each. 
Then pass hydrogen sulphide through those solutions 
with which hydrochloric acid does not give precipi- 
tates. 

With which ones does hydrogen sulphide give pre- 
cipitates ? 

3. To those solutions with which hydrogen sulphide 
does not give precipitates add ammonium sulphide. 


Which solutions give precipitates with ammonium — 


sulphide? 


ee ee 





HOW TO ANALYZE SUBSTANCES. 


In order to analyze substances chemists make use of 
reactions like those you have studied in Experiments 
132, 133, 184, 135, and 136. To learn to. analyze 
complicated substances, long practice and careful study 
of a great many facts are necessary. But simple sub- 
stances can be analyzed by the aid of such facts as you 
have already learned. You have learned, for example, 
that certain chlorides are insoluble in water; that cer- 
tain sulphides are insoluble in dilute hydrochloric acid ; 
and that other sulphides which are soluble in dilute 
hydrochloric acid are insoluble in neutral or alkaline 
solutions. Advantage is taken of these and other similar 
facts to classify substances according to their reactions. 
A convenient classification for purposes of analysis is the 
following : 


Group I. Metals whose chlorides are insoluble or dif- 
ficultly soluble in water. This group includes : 
Sriver, lead, and mercury in mercurous salts. 


Group II. Metals not included in Group I, whose sul- 
phides are insoluble in dilute hydrochloric or nitric 
acid. This group includes: Copper, mercury (as 
mercuric salt), besmuth, antemony, arsenic, and tin. 


Group III. Metals not included in Groups I and II, 
whose sulphides are precipitated by ammonium 
sulphide and ammonia. This group includes: 
Aluminium, chromium, nickel, cobalt, iron, zinc, 
and manganese. 


Group IV. Metals not included in Groups I, II, and 
III, which are precipitated by ammonium carbo- 
nate, ammonia, and ammonium ¢ghloride. This 
group includes: Larium, strontium, and calciwm. 


Grove V. Metals not included in Groups I, II, III, 
and IV, which are precipitated by disodium phos- 
phate, HNa,PO,, ammonia, and ammonium chlo- 
ride. This group includes: Jagnesium. 


Group VI. Metals not included in Groups I, II, ITI, 
IV,and V. This group includes: Sodiwm, potas- 


sum, and ammonium. 


1. Now, suppose you have a substance given you for 
analysis. ‘The first thing to do is to get the substance in 
solution. See whether it dissolves in water. If it does 
not, try dilute hydrochloric acid. If it does not dissolve 
in hydrochloric acid, try nitric acid; and if it does not 
dissolve in nitric acid, try a mixture of nitric and hydro- 
-chloric acids. If concentrated acid is used, evaporate to 
dryness on a water-bath before proceeding further. — 
Then dissolve in water, and add a few drops of hydro- 
chloric acid. If a precipitate is formed, continue to add 
the acid drop by drop until a precipitate is no longer 
formed. Filter and wash. 


What may this precipitate contain? 

2. Pass hydrogen sulphide through the filtrate for 
some time and let stand. Filter and wash. 

If a precipitate is formed, what may it contain? 

3. Add ammonia and ammonium sulphide to the fil- 
trate. Filter and wash. 

If a precipitate is formed, what may it contain? 

4, Add ammonium carbonate, ammonia, and am- 
monium chloride to the filtrate. Filter and wash. 

If a precipitate is formed, what may it contain? 

5. Add disodium phosphate, ammonia, and ammonium 
chloride to the filtrate. Filter and wash. 

If a precipitate is formed, what may it contain? 

What may be in the filtrate? 


a a a a ee = 


EXAMPLES FOR PRACTICE. 


Before attempting anything in the way of systematic 
analysis it will be well to experiment in a more general 
way, with the object of determining which one of a given 
list of substances a certain specimen is. 

The list below contains the names of the principal 
substances with which you have thus far had to deal 
in your work. You have handled them and have seen 
how they act toward different substances. Suppose now 
that a substance is given you, and you know simply 
that it is one of those named in the list, how would you 
go to work to find out which one it is? You havea 
right to judge by anything in the appearance or in the 
conduct of the substance. If you reach a conclusion, 
see whether you are right by further experiments. 
After your work is finished write out a clear account of 
what you have done, and state clearly your reasons for 
the conclusion which you have reached. 

For example, suppose sodium chloride is given you. 
You see it is a white solid. On heating it in a small 
tube you see that it does not melt, but it breaks up into 
smaller pieces with a crackling sound. It is soluble in 
water. Hydrochloric acid causes no change when added 
to a little of the solid. Is it a carbonate? Sulphuric 
acid causes evolution of agas. Has this an odor? How 


does it appear when allowed to escape into the air? Is 
it nitric acid? Collect some of it in water. How does 
this solution act on a solution of silver nitrate? By this 
time you have evidence that you are dealing with a 
chloride, but you do not yet know which chloride it is, 
It cannot be ammonium chloride. Why? It may be 
either potassium or sodium chloride. Moisten a clean 
platinum wire with distilled water, dip it into the pow- 
dered substance, and heat in a flame. What color?* 
You now have good reasons for believing that the sub- 
stance you are dealing with is sodium chloride. To con. 
vince yourself, get a small piece of sodium chloride from 
the bottle known to contain it, and make a series of 
parallel experiments with this and see whether you get 
exactly the same results that you got with the specimen 
you were examining. If not, account for the differences. 
By careful work there will be no serious difficulty in 
determining which one of the substances in the list you 
are dealing with. : 





*In making the color-test, always examine the flame through a 
piece of blue glass before deciding that the substance is a sodium salt. 
The color of the potassium flame is readily obscared by traces of so- 
dium salts which may be present as impurities. (See Exp. 110, 4.) 


LIST OF SUBSTANCES FOR EXAMINATION. 


1. Sugar. 19. Manganese dioxide. 

2. Mercuric oxide. 20. Charcoal. 

3. Cale-spar. 21. Calcium sulphate (Gyp- 

4. Marble. sum). 

5. Copper. 22. Copper oxide. 

6. Hydrochloric acid. 23. Ammonium chloride. 

7. Nitrie acid. 24. Calcium oxide (Quicx- 

8. Sulphuric acid. lime). 

9. Zinc. 25. Sodium nitrate. 

Oe bin. 26. Ammonium nitrate. 

11. Tartaric acid. 27. Sodium chloride. 

12. Sodium carbonate. 28. Potassium bromide. 

13. Ferrous sulphate (Cop- 29. Potassium iodide. 
peras). 30. Iron sulphide. 

14. Roll-sulphur. 381. Potassium carbonate. 

15. Iron-filings. | 32. Potassium nitrate. _ 

16. Carbon bisulphide. 33. Potassium bichromate. 

17. Lead. 34. Red lead (Minium). 

18. Potassium chlorate. 35. Lead carbonate. 


[The teacher will, of course, select the substance and 
give it to the pupil without any suggestion as to what it 
is. After the pupil has shown that he can tel! with cer- 
tainty which substance he has, some simple mixtures of 
substances selected from the above list may next be given 
for examination. Thus charcoal and copper oxide; zinc 
and tin; mercuric oxide and iron filings; ete., etc. 





STUDY :OF GROUP I, 


EXPERIMENT 137. 


1. Prepare dilute solutions of silver nitrate, AgNO,, 
lead nitrate, Pb(NO,),, and mercurous nitrate, HgNO,,. 
_ 2. Add to a small quantity of each separately in 
test-tubes a little hydrochloric acid. 

What is formed? 

3. Heat each tube with contents, and then let cool. 
_ What difference do you observe ? 

4. After cooling, add a little ammonia to the con- 
tents of each tube. 

What takes place in each case ? 

How could you distinguish between silver, lead, and 
mercury ? 

5. Mix the solutions of silver eee lead nitrate, 
and mercurous nitrate, and add a little of the mixture 
to considerable water in a test-tube. Add hydro- 
chlorie acid as long as it causes the formation of a 
precipitate. Heat to boiling. Filter rapidly and 
wash with hot water. 

What is in the filtrate, and what is on the filter ? 

6. Let the filtrate cool. 

What evidence have you that there is anything pres- 
ent in it? 

7. Add sulphuric acid to a little of the filtrate. 

8. Pass hydrogen sulphide through a little of the 
filtrate. 

9. Pour ammonia on the filter, and wash out with 
water. Then acidify the filtrate with nitric acid. 

What evidence do you get of the presence of silver 
and of mercury ? 


STUDY OF GROUP II. 


EXPERIMENT 138. 


1. Prepare dilute solutions of copper sulphate, mer- 
curic chloride, arsenic chloride (see Exp. 95), and of 
tin chloride (made by dissolving tin in hydrochloric 
acid). [Bismuth and antimony are omitted, as their 
presence gives rise to difficulties hard to deal with 
intelligently at this stage.] Add a little hydrochloric 
acid to the solutions of copper sulphate and of mer- 
curic chloride. 

2. Pass hydrogen sulphide through a small quan- 
tity of each of the solutions. 

What takes place? What are the substances 
formed ? 

3. Filter and wash. Treat each precipitate with a 
solution of ammonium sulphide. 


What takes place? Add dilute sulphuric acid ta 


the filtrates. 

What takes place? 

4. Treat the precipitates obtained from the copper 
and the mercury salts with warm concentrated nitric 
acid. 


Does either one dissolve easily? What is the color 


of the solution ? 
5. Treat a little of the solution obtained in 4 with 
ammonia. 


What is the result ? Howcan you detect the pres- — 


ence of copper ? 

6. Treat with a mixture of nitric and hydrochloric 
acid the precipitate which is not readily dissolved by 
nitric acid alone. Evaporate the acid. Add water, 
and then a solution of tin chloride. 


lil alte 





EXPERIMENT 138—( Continued). 


What is formed when tin is dissolved in hydro- 
chloric acid ? 

What other compound of tin and chlorine is there ? 

[When stannous chloride, SnCl,, acts upon mercuric 
ehloride, HgCl,, the former takes a part or all of the 
chlorine from the latter, forming either mercurous 
chloride, HgCl, or mercury, according to the relative 
amounts of the two substances present, thus: 


2HgCl, + SnCl, = 2HgCl + SnCl, ;sx 
HgCl, + SnCl, = Hg + SnCl,.] 


7. Treat the precipitate obtained in the case of the 
arsenic with 4-5 cubic centimeters of a concentrated 
solution of ammonium carbonate. To the solution 
add hydrochloric acid and a few crystals of potassium 
chlorate, and boil until chlorine is no longer given off. 
Add ammonia, ammonium chloride, and magnesium 
sulphate to the solution. [The precipitate is ammo- 
nium magnesium arsenate, NH,MgAsO,.| Compare 
Experiment 98a. | 

8. Dissolve the tin precipitate in dilute hydrochloric 
acid. Add a few small pieces of zinc. Dissolve in 
hydrochloric acid the tin which separates. 

What will the solution thus obtained contain ? 

What should take place on adding the solution to a 
solution of mercuric chloride? Try it.. 

Mix the solutions prepared in 1, and proceed as 
follows : 

9. Pass hydrogen sulphide until the liquid smells 
strongly of it (showing that the metals have been 
completely precipitated as sulphides) ; filter; wash ; 


0%, 


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EXPERIMENT 138—( Continued). 


treat the precipitate with ammonium sulphide ; filter ; 
wash. 

What is now in solution ? 

What is in the filter ? 

10. Treat the solution with dilute sulphuric acid. 
Filter; wash. Treat the precipitate thus obtained 
with concentrated ammonium carbonate. Filter; 


wash. Treat the solution as directed in 7; and the 


precipitate as in 8. 

11. Treat with a mixture of warm concentrated nitric 
and hydrochloric acids the precipitate left after treat- 
ing with ammonium sulphide asin 9. Test for copper 
asin 5; and for mercury as in 6. 





STUDY OF GROUP IIL 


ALUMINIUM. 


EXPERIMENT 139. 


1. Prepare a solution of ordinary alum. [What is 
ordinary alum ?] 

2. Add to this solution ammonia, ammonium chlo- 
ride, and ammonium sulphide. Filter and wash. Treat 
the precipitate with hydrochloric acid; and then treat 
the solution thus obtained with ammonium chloride 
and ammonia. 

[Aluminium does not form a sulphide; but the hy- 
droxide, Al(OH),, is formed when ammonia, ammoni- 
um chloride, and ammonium sulphide are added to a 
solution of its salts. When the hydroxide is treated 
with hydrochloric acid it is converted into the chlo- 
ride, AICI,, which dissolves ; and when the solution of 
the chloride is treated with ammonia the hydroxide is 
precipitated : 


AICI, + 8NH, -+ 3H,O = Al(OH), + 3NH,CL.] 


3. Dissolve the precipitate of aluminium hydroxide, 
Al(OH),, in as little hydrochloric acid as possible, and 
add a cold solution of sodium hydroxide. Boil the 
solution thus obtained. 

4, After cooling slowly add dilute hydrochloric acid. 
When the alkali is neutralized, aluminium hydroxide, 
Al(OH),, will be precipitated. It will dissolve on the 
addition of more acid; and from the solution thus ob- 
tained the hydroxide can be precipitated by a solution 
of ammonia. 













CHROMIUM. 


EXPERIMENT 140. 





' J. Prepare a solution of chromic shlondes fox 
directed in Experiment 1230. 

2. Treat the solution as under 2 Aue 3, Exper in 
139, and note the differences. rae ey 


chromium ? 


ey 


nai 
wi) 3 





IRON. 


EXPERIMENT 141. 


1. Prepare a solution of ferrous chloride. [See 
Experiment 119, 1.] 

2. Convert a part of this into ferric chloride. [See 
Experiment 119, 4.] 

3. Treat each of these solutions with ammonia and 
ammonium sulphide. 

[The precipitate is the same in both cases, and the 
action is represented thus : 


FeCl, + (NH,),8 =FeS + 2NH,Cl; 
2FeCl, + 3(NH,),S = 2FeS + 6NH,Cl-+8.] 


4. Dissolve the precipitate in hydrochloric acid. 
[FeS +2HCl = FeCl, + H,S.] 


5. Convert the ferrous into ferric chloride. [See 
Experiment 119, 4.] 

6. Treat with ammonium chloride and ammonia. 
Filter and wash. Treat the precipitate as directed un- 
der 3, Experiment 139. 

What differences are there between aluminium, 
chromium, and iron? 

7. Filter ; dissolve the precipitate in hydrochloric 
acid ; and treat with a solution of potassium ferrocyan- 
ide (yellow prussiate of potash), K,Fe(CN),. 





~~ ip nn 
SS 


ZINC. 


EXPERIMENT 142. 


1. Prepare a dilute solution of zinc sulphate. 

2. Treat with ammonia and ammonium sulphide. 
What is the color of the precipitate ? The composition 
is ZnS. 

3. Dissolve in dilute hydrochloric acid. 


Yn8 + 2HCl — ZnCl, + HS. 


4. Treat with ammonium chloride and ammonia. Is 
a precipitate formed ? 

5. Add enough hydrochloric acid to give the solu- 
tion an acid reaction, and then add sodium acetate, 
NaC,H,O,: ; 

ZnCl, + 2NaC,H,O, = 2NaCl + Zn(C,H,0,),. 

6. Pass hydrogen sulphide through the solution. 
The white precipitate is zinc sulphide, ZnS. 

What differences are there between aluminium, chro- 
mium, iron, and zinc? How could they be separated 
and detected if present in the same solution ? 

It will be well for the teacher to prepare solutions 
containing two or more members of Group III, and to 
give them to the pupil for analysis. 





SEPARATION OF ELEMENTS OF GROUP IIL. 


EXPERIMENT 144. 


1. Mix dilute solutions of alum, chromic chloride 
(prepared as in Experiment 1230), ferrous chloride 
(prepared as in Experiment 119), zinc sulphate, and 
manganese chloride. 

2. Treat with ammonia, ammonium chloride, and 
ammonium sulphide. Filter and wash. 

3. Treat the precipitate with dilute hydrochloric 
acid; treat with nitric acid to convert ferrous chloride 
into ferric chloride (Experiment 119, 4); and then 
treat the solution thus obtained with ammonium chlo- 
ride and ammonia. 
~ What have you in the precipitate? (Label this A.) 

What in the solution? (Label this B.) 

4. Dissolve the precipitate in a little dilute hydro- 
chloric acid, and add a cold solution of sodium hy- 
droxide, more than enough to neutralize the hydro- 
chloric acid. Filter; dissolve the precipitate in 
hydrochloric acid, and treat with a solution of po- 
tassium ferrocyanide, K,Fe(CN),. [See Experiment 
141, 7.] Boil the filtrate from the precipitate of ferric | 
hydroxide. What is precipitated? Treat the filtrate 
as directed in Experiment 1939, 4. | 

5. Treat the solution B (see under 3 above) as 
directed under 5 and 6, Experiment 142; and under 
3, Experiment 148. Examine mixtures containing 
members of Group III. 





STUDY OF GROUP IV. 


CALCIUM. 
EXPERIMENT 145. 


1. Prepare a solution of calcium chloride by dis- 
solving a little calcium carbonate (marble) in hydro- 
chloric acid. What is the reaction ? ) 

2. Treat with ammonium chloride, ammonia, and 
ammonium carbonate, (NH,),CO,. Filter and wash. 

What takes place? Write the equation. 

3. Dissolve the precipitate in dilute hydrochloric 
acid. Treat a small part of this solution with a solution 
of calcium sulphate in water. Treat another small part 
with ammonia and ammonium oxalate, (NH,),C,O,. 
The precipitate is calcium oxalate, CaC,O,. 

Does a solution of calcium chloride give a precip- 
itate when treated with a solution of calcium sul- 
phate ? 





BARIUM. 


EXPERIMENT 146. 


1. Prepare a dilute solution of barium chloride in 
water. 

2. Treat as directed under 2, preceding Experiment. 

3. Dissolve the precipitate in dilute hydrochloric 
acid. Treat a small part of this solution with a solu- 
tion of calcium sulphate in water. 

What difference do you notice between the conduct 
of calcium and that of barium? 

How could you detect barium and calcium when 


present in the same solution? Mix the solutions of 


barium and calcium chlorides, and try the reactions 
described in Experiments 145 and 146. 





STUDY OF GROUP V. 
MAGNESIUM. 


EXPERIMENT 147. 


1. Prepare a dilute solution of magnesium sulphate 
in water. 

2. Add ammonium chloride, ammonia, and disodium 
phosphate, HNa,PO.. 

The precipitate formed is ammonium magnesium 
phosphate, NH,MgPO,. What similar precipitate 
has already been obtained? (See Experiment 138, 7.) 

3. Mix solutions of barium chloride, calcium chlo- 
ride, and magnesium chloride, and see whether you 
can detect the three metals by means of the reactions 
described in Experiments 145, 146, and 147, 





STUDY OF GROUP VL 


EXPERIMENT 148, 


1. Potassium can be detected by means of the color 
it gives to a flame (see Experiment 110), and also by 
the fact that when chlorplatinic acid, H,PtCl,, is added 
to a solution of a potassium salt, the salt, K,PtCl,, is 
precipitated. (See Experiment 110a.) Try this. 

2. Sodium is detected by means of the flame reac- 
tion (see Experiment 110). 

3. Ammonium salts are detected by adding an al- 
kali, when ammonia gas is given off, and this is easily 
recognized by its odor or by its action on a moistened 
piece of red litmus-paper. 





GENERAL DIRECTIONS. 


By the aid of the reactions thus far studied you will 
find it possible to analyze substances which contain the 
following metals either alone or mixed together: 

Silver, lead, mercury, copper, tin, arsenic, aluminium, 
chromium, iron, zinc, manganese, calcium, barium, 
magnesium, potassium, sodium, and ammonium. After 
the metals have been detected, the next question to be 
answered is: In what forms of combination were they 
present in the original substance taken for analysis? 
Or, in other words, what salts were present? To an- 
swer this question, recall the experiments you have made 
in the general reactions of chlorides, nitrates, sulphates; 
and carbonates. These are the most common salts, and, 
for the present, it will be best to confine your work to 
these. 


CLASSIFICATION OF SUBSTANCES 
STUDIED. 


It will now be well to draw up a table containing the 
names and symbols of all the substances with which you 
have had to deal, classifying them into: 

(1) Hlements and Compounds ; 

(2) Acids, Bases, and Salts. 

Under /’lements state the principal source and the 
principal method for getting each. 

Under Compounds state the source and the principal 
method for the preparation of each. 

Classify all the compounds you have had to deal with 
into: 

(1) Those which are gaseous ; 

(2) Those which are liquid ; 

(3) Those which are solid at the ordinary tempera- 
ture ; 

(4) Those solids and liquids which easily undergo 
change when heated (state what the change is, and give 
the equation expressing the change). 

Classify the compounds further into: 

(1) Those which are soluble in water without change; 

(2) Those which dissolve in water and are changed 
(state what the change is, and give the equation express- 
ing the change) ; 

(8) Those which are insoluble in water, 


WEIGHTS AND MEASURES. 


ENGLISH SYSTEM. 
Troy or Apothecaries’ Weight. 


Pound. Ounces. Drams. Scruples. Grains. Grams, 
tN ss 12 = OO ae 288 = 5760 == 872.96 
Lote Diao 24 =: 480 7 lao 
i= 3 = 60 = 3.885 
1 = 20 = 1.295 
1 = 0.0647 

Avoirdupois Weight. 
Pound. Ounces. Drams. Grains. Grams. 
1 =| 16 = 256 — 7000 = 453.25 
1 = 16 = 437.5 = 28.328 
1 = 27.343 = : Eo aay 


Imperial Measure. 


Cubic 
Galion. Pints. Fl. Ounces. Fl. Drams. Minims. Centimeters. 


ica aS 160 1280 76800 4545.86 
1 20 160 9600 568.23 

1 8 480 28.41 

1 60 3.55 


Il 
ot | | 


Nou Ue dl 
the | 


METRIC SYSTEM, 
Measures of Length. 


Meter. Decimeters. Centimeters. Millimeters. Inches, 
1 = 10 100 1000 89.37100 
1 10 3.93710 
1 0.89371 
0.03937 _ 


ll 


nou 
_ 
S 
ca) 


° 
nou i tl 


Measures of Capacity. 
Liter. Cubic Centimeters. Pints. Cubic Inches. 
1 — 1000 1.76 61.0363 . 
0.0610 
1.00 


rare 
ll 
= 
S 
= 

No Ul 


16.38 
Measures of Weight. 


Kilogram. Grams. Lbs. (Avoirdupois). Grains. 
1 = 1000 = 2.2046 = 15482.00 
1 = 0.0022 = 15.48 








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